Iture Comriburions ill

mpson R L Biomass of the middle Atlantic ld Managemem PotenshyAcademic Press New

of a tropical swamp

land study Freshwater

Biomass 18 (19RI)) 15-29

Species Screening and Biomass Trials of Woody Plants in the Semi-arid Southwest United States

Robert D Kirmse

Intrnational Resources Group Ltd (IRG) Washington DC USA

amp

James T Fisher

Dlpanmnt of Agronomy and Horticulture New Mexico State University Las Cruces New Mexico R8003 USA

Rcci cd I () Decemoer 11)87 revised version received 31 Octoher 1)88 accepted 2 November 11)88)

ABSTRACT

Species screening and selection trials are being condllcted to idemify appropriate woody species and technology for bioflie farming in the southwest United States During the initial phase of the program 26 natil( and exotic species have been tested at sites in Texas New Mexico and Ariona Second season biomass estimates indicate that initial vields of 32-85 dry Mg ha- J year- J are possible without post-eslablisment irrigation The species Atriplex canescens (Pllrsh) Nult bull Prosopis alba Griseb (Ind Leucaena leucocephala (Lam) de Wit reached canopy closure uihin two seasons of growth alld are idennfted as rapid inital hiomass producers under the semi-arid conditions ofthe study area

Key words bioenergy short rotation woody crops biomass estimations coppice Alriplex Leucaena Prosopis shrub tree species selection

Prescnt address FAO-United Nations Via Delle Torre di Caracalla 00100 Rome Italy

15 Biomass 0 144-456589S0350 - e 1989 Elsevier Science Publishers Ltd England Printed in Great Britain

16 R D Kirmse 1 T Fisher

INTRODUCTION

Land-use concepts in the semi-arid southwest United States are rapidly changing High energy costs decreasing ground water supplies and loss of productivity due to long-term erosion are making conventional crop farming increasingly less profitable Under these constraints alternative low input agriculture is essential if these marginal farmlands are to remain economically productive Short rotation woody plant farming may match the specific market and ecological niche Multiple purpose woody plant crops can provide marketable products including biofuels silichemicals and animal fodder Many woody species are well suited to arid conditions because they are deep rooted and possess physiological attrihutes allowing them to survive and produce in situations where drought and edaphic constraints preclude traditional herbaceous row crops However the information necessary to select appropriate woody species and to manage non-traditional arid-land crops is meager to nonshyexistent

In 1977 the US Department of Energy initiated the Short Rotation Woody Crops Program (SRWCP) to develop viable and cost-effective Short Rotation Intensive Culture (SRIC) technology for biofuel-producshying trees and shrubs U A southwest regional research project was initiated in 1984 as one of 17 SRWC projects established throughout the US under this national program The initial objective of this regional research project was to identify species and management guidelines appropriate for biofuel farming in the southwest United States Because of the paucity of relevant research information on woody biomass production in the southwest the immediate aim of this project was to select from a large number of candidate species and varieties those able to efficiently produce biomass under the regions environmental constraints We refer to this stage as Phase I

Specifically Phase I involves the concurrent screening and testing of species for growth and biomass production Candidate species were chosen on the basis of comparative climatic adaptability in their native hahitat Phase I activities resemble the Species Elimination Phase recommended by Burley et al 3 in which a large number of species are compared for relative performance Concurrently a select number of species for which attributes have already been documented are being tested in more intensive and longer term Production Trials The -Proshyduction Trials of this study correspond to the Species Testing Phase described by Burley et al 3

In Phase II species and varieties identified in Phase I would be grown in production trials to assess biomass production Phase II would also

d States are rapidly r supplies and loss ~ conventional crop Istraints alternative I farmlands are to )ody plant farming ~ Multiple purpose including biofuels s are well suited to )ssess physiological n situations where al herbaceous row appropriate woody IS is meager to non-

the Short Rotation and cost-effective for biofuel-producshyearch project was hed throughout thc ic of this regional Igement guidcJinc~ ted States Because m woody biomass this project was to

ties those able s environmental

inn and tcstin of eshyidate species were

ity in their native n Phase

nted arc being Trial The Proshy

ies Testing Phase

Species screening and biomass trials in the southwest USA 17

address management techniques for growing the most promising biofuel species at each site This paper discusses the Phase I projects overall research concept and reports results of species and biomass trials conshyducted in Texas New Mexico and Arizona

MATERIALS AND METHODS

Research design

The overall design of this screening and selection research is based on the randomized complete block (RCB) model Candidate species and varieties which have not been the subject of prior investigations are being screened at each site to identify the most productive genotypes by application of line plots within the replications of the RCB design In this design 8-] 0 plants of a species constitute a plot and each plot is replicated four times Plants were spaced at 2 m within rows separated by 2 m Of primary interest in this design is the effect of climate on survival The principal climatic variables monitored at each site were maximum and minimum temperatures and yearly precipitation

Selected genotypes of the species which previous investigations have shown to be most promising are being tested in Production Trials that employ square R-by-R-tree array plots Each plot containing 64 plants of one sptCies spaced 2 m x 2 m is replicated four times Within each plot the 36 innermost trees are the measurement trees for the test the outer trees will be used for destructive sampling only to avoid biased data from relaxed intraspecific competition or severe environmental constraints at the edge of the plots Four or five species have been planted to this more rigorous RCB design at each site to provide precise information on relative growth and production rates (biomass) of the various genotypes under investigation Randomization was done separately for each site

Study area

Stud sites were located in Premont Texas Las Cruces New Mexico and Glendale Arizona (Fig I) to investigate plant response to the dierse environmental conditions of the region Glendale is the dryest site under investigation and Premont is the wettest (Table 1) The Las Cruces site is the highest in elevation and is the coldest Premont represents the lowest elevation and latitude tested The potential vegetashytion types on which the study areas are established are mesqushy

~-

v

lt --bullbull ~ -shy

-

-

I~ R D K innse J T Fisher

SOUTHWEST USA bull PREMONT~

Fig I Southwest US regional SRWCP site locations

ite-Acacia-savanna in South Texas4 the middotSonoran Desert scrub in Arizona and the Chihuahua Desert scrub in New Mexico The Texas site was previously used as unimproved rangeland the New Mexico and Arizona sites were previously used as irrigated cropland

Tht project was not designed to compare plant performance among sites Rather it was designed to screen and select species believed a priori to be at least marginally suited for biofuel production at each unique site Therefore with few exceptions trial species differed among sites

OUlplanting

The seedlings were container-grown from seed in a greenhouse fl7 under

extended photoperiod Four-month-old seedlings were auger planted during July and August 1985 Before planting each site was prepared by plowing (30 em) and disking to improve soil tilth enhance water infiltration and remove weeds Minimal irrigation - sufficient only to wet the root zone - was used during the first 2 months after planting to assure seedling establishment Plants were not irrigated during the second growing season Weeds were controned at all sites throughout the study by mechanical and manual cultivation

Grmlh and biomass measurements

Plant growth and survival were monitored at each site 2 months postshyplanting (September 1985) at the end of the first growing season (November 1985) after spring regrowth (April 1986) and at the end of the second growing season (November 1986) Second-season growth and survival (measured November 1986) are reported in this paper

- v rr 10-0 ~ ~ r S I T75~ tgt nlll ~ - I (wi O~ J r r J -1

I 3 - r l omiddot r - r r I l Ill

r ~ I c ~ I o Ill 0- 0 oZ~OJ l (J~ 11 iii-Illlll l l I Ill - Ill -Ill l ni c 0 g- ~ () JJ~ 0 iii (Sl ~ E rJQ ~= 3

l tgt tgt ~ 3 - Ill ~ - _r ~ rr c ltr rt ~ 0 - - ~ c Ill ~ lt r or c lt l r - l l ll bull Ill l Ill () 3-1shy_l rrrc _ 1shyrr ~ - () 0 - r - a Ill or I T ~ r ~

rq f iii s 0 Ill (t -sect I -n - -l_ -0_-l Ill f () c rr 5 2 ~ ~ ~ c r ~ 3~cJ~-J 0loshy rr - S l 8shy middoto r ~ pound TT--rtlllfr 0 l l _ -lso ~ gtlt

~

- r-l rf=Ccc ~ poundfte orl

--~~----

(

TARLE I ~1 SOllthwest SRWCP SilL Charaeteri tie ami Current Climatic Data ~

---------------------------shy ~ Site PrellOllf Ias CrunS ( iClUllIt

~ 5 IXII New lllexicl) AiOIIlI ~

County Jim Wells Dona Ana Maricopa ~

Longitude lJIH1) W 106middot45 W 112middot01 W ~~ th~ Latitude 27middot13 N 32middot2 N 33middot26 N S

Elevation 36m 1150m 334m ~ ~

Soil series CzarDelfina GlendaleHarkey GlenharGilman Cmiddot I Soil texture Sandy loam Clay loam Clay loam Igt Soil pit 7middot7 7middot1) 7middot1) t Precipitation (long-term mean in mm) 637 243 176 Igt

S 1shyFrost free days (long-term mean) 353 11)8 353

I SmiddotInno-tfrm In 6middot7 - 3) 3middot1 ~

1985 and 1986 summaries

~ Precipitation (July-Dec 1(85) (mm) 288 2JR 82 rshy

Precipillltion (Jan-Dcc 1986 )(mm) lJlJ4 315 183 laWinter I 9H5-H() minimum temperature (OC) -44 - 7middot7 -10 Summer 11)86 maximum temperature (OC) 44middot 3Rmiddot3 45middot0 ~

~

LJSDA Soil Conservation Service County Soil Survey lAverage minimum temperature during the coldest month (January)

0

w R D Kirmse 1 T Fisher

Measurements were collected 17 months after the seedlings were field planted Plant measurements were similar for the Screening Trials and Production Trials In the Species Screening Trials (line plantings) stem height and basal diameter of the largest stem were recorded on four randomly selected trees in each of the four replications (ie 11 = 101 In the Production Trials (block plantings) height and basal diameter were recorded for all stems of each measurement tree Six randomly selected trees were measured from each ofthe four replications of the Production Trial (ie n = 24) Survival was assessed on all test plants in the Screening and Production Trials

Complete canopy closure or total occupation of the ground area was the criterion for selecting a species for biomass estimation at the end of

the second growing season Three years is usually the norm for first harvest in SRIC However in this study insolation levels were high and in the absence of competing vegetation plants fully occupied growing space within the second season of growth It follows that biomass was estimated at this stage to assess the option of employing 2-year crops for energy production

A non-destructive dimensional analysis sampling approach was used for (stimating total above-ground dry matter of the species selected This technique requires establishing a relationship between plant weight and plant dimensions having predictive value For dimensional analysis a range of plant sizes was harvested from within the second inner row of each experimental block to establish the prediction equation The basal diameter and length of each stem of tree species were recorded and the entire plant (including leaves) was weighed promptly to the nearest gram using a spring scale Six plants of each of these tree species were harvested in this manner from each site Because of the multi-stemmed habit of these plants a total of 11-12 stems (from 6 plants) were used in calculating the regression equation (Table 4) for each species however the number of individual plants used in developing the equation for each tree species was the same (ie 6) The height and two canopy diameters (the longest and that perpendicular to the longest) were measured on eight harvested Atriplex callescellS plants and those entire plants were also individually weighed A slightly larger sample number (ie eight for the shrub versus six for the trees) was destructively harvested for establishing the Atriplex regression because of the high variability in plant size The actual weights of the harvested plants were regressed

a against various plant dimensions and combinations of measurements to find the prediction equation with the highest ~ value

The regression equations established for each species were used to estimate fresh weights of the plants measured in the Production Trials

I

t o tl 11 fa K an

xze ~

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

d States are rapidly r supplies and loss ~ conventional crop Istraints alternative I farmlands are to )ody plant farming ~ Multiple purpose including biofuels s are well suited to )ssess physiological n situations where al herbaceous row appropriate woody IS is meager to non-

the Short Rotation and cost-effective for biofuel-producshyearch project was hed throughout thc ic of this regional Igement guidcJinc~ ted States Because m woody biomass this project was to

ties those able s environmental

inn and tcstin of eshyidate species were

ity in their native n Phase

nted arc being Trial The Proshy

ies Testing Phase

Species screening and biomass trials in the southwest USA 17

address management techniques for growing the most promising biofuel species at each site This paper discusses the Phase I projects overall research concept and reports results of species and biomass trials conshyducted in Texas New Mexico and Arizona

MATERIALS AND METHODS

Research design

The overall design of this screening and selection research is based on the randomized complete block (RCB) model Candidate species and varieties which have not been the subject of prior investigations are being screened at each site to identify the most productive genotypes by application of line plots within the replications of the RCB design In this design 8-] 0 plants of a species constitute a plot and each plot is replicated four times Plants were spaced at 2 m within rows separated by 2 m Of primary interest in this design is the effect of climate on survival The principal climatic variables monitored at each site were maximum and minimum temperatures and yearly precipitation

Selected genotypes of the species which previous investigations have shown to be most promising are being tested in Production Trials that employ square R-by-R-tree array plots Each plot containing 64 plants of one sptCies spaced 2 m x 2 m is replicated four times Within each plot the 36 innermost trees are the measurement trees for the test the outer trees will be used for destructive sampling only to avoid biased data from relaxed intraspecific competition or severe environmental constraints at the edge of the plots Four or five species have been planted to this more rigorous RCB design at each site to provide precise information on relative growth and production rates (biomass) of the various genotypes under investigation Randomization was done separately for each site

Study area

Stud sites were located in Premont Texas Las Cruces New Mexico and Glendale Arizona (Fig I) to investigate plant response to the dierse environmental conditions of the region Glendale is the dryest site under investigation and Premont is the wettest (Table 1) The Las Cruces site is the highest in elevation and is the coldest Premont represents the lowest elevation and latitude tested The potential vegetashytion types on which the study areas are established are mesqushy

~-

v

lt --bullbull ~ -shy

-

-

I~ R D K innse J T Fisher

SOUTHWEST USA bull PREMONT~

Fig I Southwest US regional SRWCP site locations

ite-Acacia-savanna in South Texas4 the middotSonoran Desert scrub in Arizona and the Chihuahua Desert scrub in New Mexico The Texas site was previously used as unimproved rangeland the New Mexico and Arizona sites were previously used as irrigated cropland

Tht project was not designed to compare plant performance among sites Rather it was designed to screen and select species believed a priori to be at least marginally suited for biofuel production at each unique site Therefore with few exceptions trial species differed among sites

OUlplanting

The seedlings were container-grown from seed in a greenhouse fl7 under

extended photoperiod Four-month-old seedlings were auger planted during July and August 1985 Before planting each site was prepared by plowing (30 em) and disking to improve soil tilth enhance water infiltration and remove weeds Minimal irrigation - sufficient only to wet the root zone - was used during the first 2 months after planting to assure seedling establishment Plants were not irrigated during the second growing season Weeds were controned at all sites throughout the study by mechanical and manual cultivation

Grmlh and biomass measurements

Plant growth and survival were monitored at each site 2 months postshyplanting (September 1985) at the end of the first growing season (November 1985) after spring regrowth (April 1986) and at the end of the second growing season (November 1986) Second-season growth and survival (measured November 1986) are reported in this paper

- v rr 10-0 ~ ~ r S I T75~ tgt nlll ~ - I (wi O~ J r r J -1

I 3 - r l omiddot r - r r I l Ill

r ~ I c ~ I o Ill 0- 0 oZ~OJ l (J~ 11 iii-Illlll l l I Ill - Ill -Ill l ni c 0 g- ~ () JJ~ 0 iii (Sl ~ E rJQ ~= 3

l tgt tgt ~ 3 - Ill ~ - _r ~ rr c ltr rt ~ 0 - - ~ c Ill ~ lt r or c lt l r - l l ll bull Ill l Ill () 3-1shy_l rrrc _ 1shyrr ~ - () 0 - r - a Ill or I T ~ r ~

rq f iii s 0 Ill (t -sect I -n - -l_ -0_-l Ill f () c rr 5 2 ~ ~ ~ c r ~ 3~cJ~-J 0loshy rr - S l 8shy middoto r ~ pound TT--rtlllfr 0 l l _ -lso ~ gtlt

~

- r-l rf=Ccc ~ poundfte orl

--~~----

(

TARLE I ~1 SOllthwest SRWCP SilL Charaeteri tie ami Current Climatic Data ~

---------------------------shy ~ Site PrellOllf Ias CrunS ( iClUllIt

~ 5 IXII New lllexicl) AiOIIlI ~

County Jim Wells Dona Ana Maricopa ~

Longitude lJIH1) W 106middot45 W 112middot01 W ~~ th~ Latitude 27middot13 N 32middot2 N 33middot26 N S

Elevation 36m 1150m 334m ~ ~

Soil series CzarDelfina GlendaleHarkey GlenharGilman Cmiddot I Soil texture Sandy loam Clay loam Clay loam Igt Soil pit 7middot7 7middot1) 7middot1) t Precipitation (long-term mean in mm) 637 243 176 Igt

S 1shyFrost free days (long-term mean) 353 11)8 353

I SmiddotInno-tfrm In 6middot7 - 3) 3middot1 ~

1985 and 1986 summaries

~ Precipitation (July-Dec 1(85) (mm) 288 2JR 82 rshy

Precipillltion (Jan-Dcc 1986 )(mm) lJlJ4 315 183 laWinter I 9H5-H() minimum temperature (OC) -44 - 7middot7 -10 Summer 11)86 maximum temperature (OC) 44middot 3Rmiddot3 45middot0 ~

~

LJSDA Soil Conservation Service County Soil Survey lAverage minimum temperature during the coldest month (January)

0

w R D Kirmse 1 T Fisher

Measurements were collected 17 months after the seedlings were field planted Plant measurements were similar for the Screening Trials and Production Trials In the Species Screening Trials (line plantings) stem height and basal diameter of the largest stem were recorded on four randomly selected trees in each of the four replications (ie 11 = 101 In the Production Trials (block plantings) height and basal diameter were recorded for all stems of each measurement tree Six randomly selected trees were measured from each ofthe four replications of the Production Trial (ie n = 24) Survival was assessed on all test plants in the Screening and Production Trials

Complete canopy closure or total occupation of the ground area was the criterion for selecting a species for biomass estimation at the end of

the second growing season Three years is usually the norm for first harvest in SRIC However in this study insolation levels were high and in the absence of competing vegetation plants fully occupied growing space within the second season of growth It follows that biomass was estimated at this stage to assess the option of employing 2-year crops for energy production

A non-destructive dimensional analysis sampling approach was used for (stimating total above-ground dry matter of the species selected This technique requires establishing a relationship between plant weight and plant dimensions having predictive value For dimensional analysis a range of plant sizes was harvested from within the second inner row of each experimental block to establish the prediction equation The basal diameter and length of each stem of tree species were recorded and the entire plant (including leaves) was weighed promptly to the nearest gram using a spring scale Six plants of each of these tree species were harvested in this manner from each site Because of the multi-stemmed habit of these plants a total of 11-12 stems (from 6 plants) were used in calculating the regression equation (Table 4) for each species however the number of individual plants used in developing the equation for each tree species was the same (ie 6) The height and two canopy diameters (the longest and that perpendicular to the longest) were measured on eight harvested Atriplex callescellS plants and those entire plants were also individually weighed A slightly larger sample number (ie eight for the shrub versus six for the trees) was destructively harvested for establishing the Atriplex regression because of the high variability in plant size The actual weights of the harvested plants were regressed

a against various plant dimensions and combinations of measurements to find the prediction equation with the highest ~ value

The regression equations established for each species were used to estimate fresh weights of the plants measured in the Production Trials

I

t o tl 11 fa K an

xze ~

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

lt --bullbull ~ -shy

-

-

I~ R D K innse J T Fisher

SOUTHWEST USA bull PREMONT~

Fig I Southwest US regional SRWCP site locations

ite-Acacia-savanna in South Texas4 the middotSonoran Desert scrub in Arizona and the Chihuahua Desert scrub in New Mexico The Texas site was previously used as unimproved rangeland the New Mexico and Arizona sites were previously used as irrigated cropland

Tht project was not designed to compare plant performance among sites Rather it was designed to screen and select species believed a priori to be at least marginally suited for biofuel production at each unique site Therefore with few exceptions trial species differed among sites

OUlplanting

The seedlings were container-grown from seed in a greenhouse fl7 under

extended photoperiod Four-month-old seedlings were auger planted during July and August 1985 Before planting each site was prepared by plowing (30 em) and disking to improve soil tilth enhance water infiltration and remove weeds Minimal irrigation - sufficient only to wet the root zone - was used during the first 2 months after planting to assure seedling establishment Plants were not irrigated during the second growing season Weeds were controned at all sites throughout the study by mechanical and manual cultivation

Grmlh and biomass measurements

Plant growth and survival were monitored at each site 2 months postshyplanting (September 1985) at the end of the first growing season (November 1985) after spring regrowth (April 1986) and at the end of the second growing season (November 1986) Second-season growth and survival (measured November 1986) are reported in this paper

- v rr 10-0 ~ ~ r S I T75~ tgt nlll ~ - I (wi O~ J r r J -1

I 3 - r l omiddot r - r r I l Ill

r ~ I c ~ I o Ill 0- 0 oZ~OJ l (J~ 11 iii-Illlll l l I Ill - Ill -Ill l ni c 0 g- ~ () JJ~ 0 iii (Sl ~ E rJQ ~= 3

l tgt tgt ~ 3 - Ill ~ - _r ~ rr c ltr rt ~ 0 - - ~ c Ill ~ lt r or c lt l r - l l ll bull Ill l Ill () 3-1shy_l rrrc _ 1shyrr ~ - () 0 - r - a Ill or I T ~ r ~

rq f iii s 0 Ill (t -sect I -n - -l_ -0_-l Ill f () c rr 5 2 ~ ~ ~ c r ~ 3~cJ~-J 0loshy rr - S l 8shy middoto r ~ pound TT--rtlllfr 0 l l _ -lso ~ gtlt

~

- r-l rf=Ccc ~ poundfte orl

--~~----

(

TARLE I ~1 SOllthwest SRWCP SilL Charaeteri tie ami Current Climatic Data ~

---------------------------shy ~ Site PrellOllf Ias CrunS ( iClUllIt

~ 5 IXII New lllexicl) AiOIIlI ~

County Jim Wells Dona Ana Maricopa ~

Longitude lJIH1) W 106middot45 W 112middot01 W ~~ th~ Latitude 27middot13 N 32middot2 N 33middot26 N S

Elevation 36m 1150m 334m ~ ~

Soil series CzarDelfina GlendaleHarkey GlenharGilman Cmiddot I Soil texture Sandy loam Clay loam Clay loam Igt Soil pit 7middot7 7middot1) 7middot1) t Precipitation (long-term mean in mm) 637 243 176 Igt

S 1shyFrost free days (long-term mean) 353 11)8 353

I SmiddotInno-tfrm In 6middot7 - 3) 3middot1 ~

1985 and 1986 summaries

~ Precipitation (July-Dec 1(85) (mm) 288 2JR 82 rshy

Precipillltion (Jan-Dcc 1986 )(mm) lJlJ4 315 183 laWinter I 9H5-H() minimum temperature (OC) -44 - 7middot7 -10 Summer 11)86 maximum temperature (OC) 44middot 3Rmiddot3 45middot0 ~

~

LJSDA Soil Conservation Service County Soil Survey lAverage minimum temperature during the coldest month (January)

0

w R D Kirmse 1 T Fisher

Measurements were collected 17 months after the seedlings were field planted Plant measurements were similar for the Screening Trials and Production Trials In the Species Screening Trials (line plantings) stem height and basal diameter of the largest stem were recorded on four randomly selected trees in each of the four replications (ie 11 = 101 In the Production Trials (block plantings) height and basal diameter were recorded for all stems of each measurement tree Six randomly selected trees were measured from each ofthe four replications of the Production Trial (ie n = 24) Survival was assessed on all test plants in the Screening and Production Trials

Complete canopy closure or total occupation of the ground area was the criterion for selecting a species for biomass estimation at the end of

the second growing season Three years is usually the norm for first harvest in SRIC However in this study insolation levels were high and in the absence of competing vegetation plants fully occupied growing space within the second season of growth It follows that biomass was estimated at this stage to assess the option of employing 2-year crops for energy production

A non-destructive dimensional analysis sampling approach was used for (stimating total above-ground dry matter of the species selected This technique requires establishing a relationship between plant weight and plant dimensions having predictive value For dimensional analysis a range of plant sizes was harvested from within the second inner row of each experimental block to establish the prediction equation The basal diameter and length of each stem of tree species were recorded and the entire plant (including leaves) was weighed promptly to the nearest gram using a spring scale Six plants of each of these tree species were harvested in this manner from each site Because of the multi-stemmed habit of these plants a total of 11-12 stems (from 6 plants) were used in calculating the regression equation (Table 4) for each species however the number of individual plants used in developing the equation for each tree species was the same (ie 6) The height and two canopy diameters (the longest and that perpendicular to the longest) were measured on eight harvested Atriplex callescellS plants and those entire plants were also individually weighed A slightly larger sample number (ie eight for the shrub versus six for the trees) was destructively harvested for establishing the Atriplex regression because of the high variability in plant size The actual weights of the harvested plants were regressed

a against various plant dimensions and combinations of measurements to find the prediction equation with the highest ~ value

The regression equations established for each species were used to estimate fresh weights of the plants measured in the Production Trials

I

t o tl 11 fa K an

xze ~

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

- v rr 10-0 ~ ~ r S I T75~ tgt nlll ~ - I (wi O~ J r r J -1

I 3 - r l omiddot r - r r I l Ill

r ~ I c ~ I o Ill 0- 0 oZ~OJ l (J~ 11 iii-Illlll l l I Ill - Ill -Ill l ni c 0 g- ~ () JJ~ 0 iii (Sl ~ E rJQ ~= 3

l tgt tgt ~ 3 - Ill ~ - _r ~ rr c ltr rt ~ 0 - - ~ c Ill ~ lt r or c lt l r - l l ll bull Ill l Ill () 3-1shy_l rrrc _ 1shyrr ~ - () 0 - r - a Ill or I T ~ r ~

rq f iii s 0 Ill (t -sect I -n - -l_ -0_-l Ill f () c rr 5 2 ~ ~ ~ c r ~ 3~cJ~-J 0loshy rr - S l 8shy middoto r ~ pound TT--rtlllfr 0 l l _ -lso ~ gtlt

~

- r-l rf=Ccc ~ poundfte orl

--~~----

(

TARLE I ~1 SOllthwest SRWCP SilL Charaeteri tie ami Current Climatic Data ~

---------------------------shy ~ Site PrellOllf Ias CrunS ( iClUllIt

~ 5 IXII New lllexicl) AiOIIlI ~

County Jim Wells Dona Ana Maricopa ~

Longitude lJIH1) W 106middot45 W 112middot01 W ~~ th~ Latitude 27middot13 N 32middot2 N 33middot26 N S

Elevation 36m 1150m 334m ~ ~

Soil series CzarDelfina GlendaleHarkey GlenharGilman Cmiddot I Soil texture Sandy loam Clay loam Clay loam Igt Soil pit 7middot7 7middot1) 7middot1) t Precipitation (long-term mean in mm) 637 243 176 Igt

S 1shyFrost free days (long-term mean) 353 11)8 353

I SmiddotInno-tfrm In 6middot7 - 3) 3middot1 ~

1985 and 1986 summaries

~ Precipitation (July-Dec 1(85) (mm) 288 2JR 82 rshy

Precipillltion (Jan-Dcc 1986 )(mm) lJlJ4 315 183 laWinter I 9H5-H() minimum temperature (OC) -44 - 7middot7 -10 Summer 11)86 maximum temperature (OC) 44middot 3Rmiddot3 45middot0 ~

~

LJSDA Soil Conservation Service County Soil Survey lAverage minimum temperature during the coldest month (January)

0

w R D Kirmse 1 T Fisher

Measurements were collected 17 months after the seedlings were field planted Plant measurements were similar for the Screening Trials and Production Trials In the Species Screening Trials (line plantings) stem height and basal diameter of the largest stem were recorded on four randomly selected trees in each of the four replications (ie 11 = 101 In the Production Trials (block plantings) height and basal diameter were recorded for all stems of each measurement tree Six randomly selected trees were measured from each ofthe four replications of the Production Trial (ie n = 24) Survival was assessed on all test plants in the Screening and Production Trials

Complete canopy closure or total occupation of the ground area was the criterion for selecting a species for biomass estimation at the end of

the second growing season Three years is usually the norm for first harvest in SRIC However in this study insolation levels were high and in the absence of competing vegetation plants fully occupied growing space within the second season of growth It follows that biomass was estimated at this stage to assess the option of employing 2-year crops for energy production

A non-destructive dimensional analysis sampling approach was used for (stimating total above-ground dry matter of the species selected This technique requires establishing a relationship between plant weight and plant dimensions having predictive value For dimensional analysis a range of plant sizes was harvested from within the second inner row of each experimental block to establish the prediction equation The basal diameter and length of each stem of tree species were recorded and the entire plant (including leaves) was weighed promptly to the nearest gram using a spring scale Six plants of each of these tree species were harvested in this manner from each site Because of the multi-stemmed habit of these plants a total of 11-12 stems (from 6 plants) were used in calculating the regression equation (Table 4) for each species however the number of individual plants used in developing the equation for each tree species was the same (ie 6) The height and two canopy diameters (the longest and that perpendicular to the longest) were measured on eight harvested Atriplex callescellS plants and those entire plants were also individually weighed A slightly larger sample number (ie eight for the shrub versus six for the trees) was destructively harvested for establishing the Atriplex regression because of the high variability in plant size The actual weights of the harvested plants were regressed

a against various plant dimensions and combinations of measurements to find the prediction equation with the highest ~ value

The regression equations established for each species were used to estimate fresh weights of the plants measured in the Production Trials

I

t o tl 11 fa K an

xze ~

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

w R D Kirmse 1 T Fisher

Measurements were collected 17 months after the seedlings were field planted Plant measurements were similar for the Screening Trials and Production Trials In the Species Screening Trials (line plantings) stem height and basal diameter of the largest stem were recorded on four randomly selected trees in each of the four replications (ie 11 = 101 In the Production Trials (block plantings) height and basal diameter were recorded for all stems of each measurement tree Six randomly selected trees were measured from each ofthe four replications of the Production Trial (ie n = 24) Survival was assessed on all test plants in the Screening and Production Trials

Complete canopy closure or total occupation of the ground area was the criterion for selecting a species for biomass estimation at the end of

the second growing season Three years is usually the norm for first harvest in SRIC However in this study insolation levels were high and in the absence of competing vegetation plants fully occupied growing space within the second season of growth It follows that biomass was estimated at this stage to assess the option of employing 2-year crops for energy production

A non-destructive dimensional analysis sampling approach was used for (stimating total above-ground dry matter of the species selected This technique requires establishing a relationship between plant weight and plant dimensions having predictive value For dimensional analysis a range of plant sizes was harvested from within the second inner row of each experimental block to establish the prediction equation The basal diameter and length of each stem of tree species were recorded and the entire plant (including leaves) was weighed promptly to the nearest gram using a spring scale Six plants of each of these tree species were harvested in this manner from each site Because of the multi-stemmed habit of these plants a total of 11-12 stems (from 6 plants) were used in calculating the regression equation (Table 4) for each species however the number of individual plants used in developing the equation for each tree species was the same (ie 6) The height and two canopy diameters (the longest and that perpendicular to the longest) were measured on eight harvested Atriplex callescellS plants and those entire plants were also individually weighed A slightly larger sample number (ie eight for the shrub versus six for the trees) was destructively harvested for establishing the Atriplex regression because of the high variability in plant size The actual weights of the harvested plants were regressed

a against various plant dimensions and combinations of measurements to find the prediction equation with the highest ~ value

The regression equations established for each species were used to estimate fresh weights of the plants measured in the Production Trials

I

t o tl 11 fa K an

xze ~

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

1( r were field

fter the secd I~g~ Trib and [or the Scrcemng

pllntlnls) ~hm I IInc bull e Tria s I cd on four - were recorl tern = Ih) In r replicatIOns ~ r were

d hasal dlameh Ight an d )mlv selected

e SIX ran l tnt r~ f the Production rcplicatlOns 0 h ScreeningaH test plants 10 t e

d r was f h roun uIpatlOn 0 t ~ ~ at thc end of

middots estimation fomas m for Ifst By thc nor s IS usua h h and

levels ere Ie InsolatIOn d growm pant~ fuHy OCCUpl~ ISS wa~ th It foHows that hlommiddot for

bull 1 1-vear crops)n 01 employmg -

roach was uscd sis samphng app I t d This atter of the species ~e ec ~ ht ndbull Int wellh h tween p bull ~

u

)n~ Ip e n1 analvsls a nsWIlue For dlmc I inner ow ofnt n within the seco The basal

Utlon1e predlctll1n C1 d I lOti the were recor cl bull e ~peCies I Lth nlrest ramt v to C ~

d promp ies were h of these tree ~pec d

eac f h muti-~temme B Cluse 0 tedIte e ~ I t were use 10m h pm S)stems1 rO however

I t) for each spcu~~ h e h eLuatlOn lor eac

in developmg t e P diameters h d twO CLmo

chell tm urcd on ~ t) were medS

to the longes phnts were d those entire ts an I I ellht lorI num(ler c e

larger samp e I hare~ted for ) wa~ destrUctl ~I ~h rl hilitv in f the 11 bull L bccau~c 0 ~ r rere~sed d phnts ~ ~ ee harcste r ments to t

d comhinations 01 m~LISU e ~

h h st rC alue d t Ig e were use 0each p~ue~ I d for h production Tria s

measured 10 t ~

-shy

21Species screening and biomass (rias ill sOlllh-wes( UA

Fresh weights were converted to dry weights by the use of conversion coefficients (dry weightwet weight) which were calculated for each species by harvesting two whole-plant samples (including leaves) for each species from each site The samples were weighed fresh dried in a forced air oven at 45degC until a constant weight was obtained and weighed again Per tree weight estimates were converted to dry Mg ha - I

on the basis of 2500 trees ha - I at a 2 m x 2 m spacing All biomass results are therefore expressed on a dry matter basis (plusmn SD)

RESULTS

Climatic summaries and site characteristics are included in Table 1 Climatic data and seasonal survival and growth assessments are reported elsewhere~i

Species screening trial

Premot Texas All species except Casllarina equisetifolia L survived the winter season (Tablc 2) The winter low temperature was - 44degC (December 1985) Most Lellcaena K340 stems froze back but all plants resprouted vigorshyow-Iy in the spring of 1986 All Acacia pennatlila (Schlect and Cham) Benth stems died back over the winter but most plants survived and produced sprouts the following spring At Premont Lellmenu K340 grew most rapidly and survival was excellent Lellcaenea K340 is a cross between L pulverulema (Schlecht) Benth and L leucocephala Lellcaena plllventlema is native to South Texas The Prosopis alba B2V50 and Acacia pennatula are also among the more promising spccies at this site The Prosopis alba clone B2V 50 is the only plant that was vegetatively propagated in this study and is a superior selection of that species1(l

Las Cnlces New Mexico Three varieties of Lellcaena were planted at this site to explore the feasibility of producing annual crops or of harvesting resprouted shoots of these fast-growers All Leucaenll varieties froze to the ground during the winter in which the seasonal low temperature was - 78degC (January IYXfl I Lelicaellll K340 is omitted from Table 2 because only 15 of the rootstocks resprouted after the winter Survival of the varieties K636 and K 743 exceeded 60 indicating that they may be potentially managed as annual crops Among all species in this trial Robinia pseudoacacia L

_So p

~

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

1

_-middotr ___ ----- ~------ middot- bull _ bull I bull

bull 22 R D_ Kinnse J_ T Fisher

TABLE 2 Species Screening Trials Southwest US SRWCP Growth and Survival after Second

Growing Season November 1986

Species loeatioll Height (em) Caliper (mm A ~erage 110 Sunira Stemsplam n)

Meall SD Wean SD

Prcmofll TX Acacia ahrssinica 123middot1 500 260 8-6 HI 92middot5 Acacia 11I11111a 111-2 43middot4 14middot8 6-8 1-0 9S-()

Acacia JlCllflalllla IS9middot2 47middot5 middotHmiddotl 15-9 1-0 97middot5 Lmeaclla K340 325middot3 43-0 62-1 19-2 23 97S

irosoll alha B2VSO clone 217-1 62middot2 39-6 13-4 1middot0 97S

La~ Crucc~ NM A (acia ahyssil1ica 2456 59middot4 35middot3 14-6 1middot8 6 111((1111111 microtheca 231middot9 48-4 45middot9 16middot9 1-3 96middot9 LCII((I( Ko36 3975 340 40-5 10middot4 3-3 6 middot

LCIc((Ia K 7 43 346middot8 42-0 45middot1 11-9 HI 62middot5 Irosopis alha B2V50 clone 298-2 32-6 45-8 7middot4 10 100-0 lros()pilcIiilellsis 228-9 57-4 33-] 114 1-6 100middot0 (Jltrws rirginial1a 116-4 30middot4 15-] 46 H 1000 Rohina psclldoacacia 404middot7 46() 89-4 24middot4 1-0 7~H

SlIpilllll l(hitWl 1403 35middot2 35-6 14-0 ]-2 lJO6

Glendale_ AZ 1(((i1 ahnsll1ica 127-8 37-9 19-7 6-1 1middot0 oS) (middotIIIl(IrIIlO eqllisetirolia IOL2 38-0 13middot6 6middot7 1-0 67middot5 ClipresslIs arizotlica 99-9 20middot8 17middot9 4middot2 1-0 1)75

Lelmcla K743 269-1 91-3 488 19-2 ]-1 97middot5 L(lwella K636 306-4 61-5 583 17middot7 HI ] 00-0 Lmuulw K340 2652 70-7 53-4 12middot7 HI 97middot5 iinus cldara 266 6middot7 73 ]3 ]-0 100-0 romp1 ulha B2VSO clone 130-] 519 49-2 ]4-6 1middot4 ]00middot0

Stem height and caliper when more than one stem only largest reported h= 10

grew most rapidly during the first two seasons but survival was below ~(n~) Moisture possibly became limiting in R pseudoacacia rows as rapid growth increased competition_ On the basis of total growth and survival rate Prosopis alba clone B2V50 Prosopis chilellsis (Mol) Stuntz and Eucalptus microtheca F Muell_ show promise as biofuel producers in southern New Mexico and should be included in future Production Trials

Glendale Arizona All species showed excellent survival through the winter months (Table 2) The winter low temperature was - 1degC (February 1986) Except for

~ F

bull f l

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

th and Survival after Second

H6

mn) A eragc 110 Sunlml Sfemspall ()

Sf)

g6 6middotg

I middotIf

Ilf 2 134

14() 16middot1f 104 I )middotIf

7middot4 IH

())

A-7 4middot2

) lt)2

)7middot7 72middot7

)-3

14-6

HI HI )-0

7-3 HI

I-X H n 2-0 )-0

-6 I-I HI )-2

1middot0 -(I I-() 1-) HI HI HI )-4

1f2-5 If-()

1f7-5 lt)7-5

1f7-5

6)middot

lt)(If

62middot5 65

IOO-() W()O 1(100

7X-1 If0-6

65-0 67-shylt)- 1f7-5

J()(HI

1f7- )O()middotO

IOliO

largest reported

but survival was below pseudollclcia rows as is of total growth and

s chilensis (Mol show promise as hiofucl

be included in future

the winter months (Tahle 19H61 Except for

23Species screening and biomass trials in the southwest USA

Acacia abyssinica Clos all species in this trial resisted the droughty hot conditions of the summer Temperatures of 44degC were common at midday from June to August 1986 Acacia abyssinica shoots dried out during these extremely hot and dry conditions The three Leucaellas have made the most growth to date The Prosopis alba clone B2V50 is very hardy at this site

Production Trials and biomass yields

Premont Texas In the Premont Production Trial Leucaena trees were tallest and had the largest stem diameter (Table 3) The Lellcaena canopies have closed and now compete effectively against the understory vegetation so weeding is no longer necessary in these plots Many of these plants froze to the ground during the winter Most of the Leucaena plants have multiple stems hecause of resprouting from basal buds in the spring Prosopis alba (propagated from seed) was the next largest tree in height after two growing seasons Within P alba plots canopies overlap but sunlight rcaches the understory because foliage is less dense than Leucaena PinliS eldarica Medw and Quercus virgillialla Mill were slower growers in this initial stage and therefore appear unlikely candidates for secondshyycar harvcsting

Biomass prediction equations for Lellcael1a K636 and K743 and Prosopis alha are presented in Table 4 A volume measurement of each individual main stem (113 rrr2 h where r= 12 basal caliper) provided the best coefficient of determination (r2) for Leucaena K743 and Prosopis alba Diameter alone however provided a better estimate for Leucaella K6J6 With an estimated annual production of 66 plusmn 3middot3 (SD) Mg ha

Leucaena K636 was the most productive accession evaluated at the Premont site (Table 5) Glumac ll also found Leucaena to be an efficient biomass producer in South Texas and reported yields ranging from 2middot0 to 14middot1 Mg ha - I 9 months following a severe freeze The dry matter coefficients of our study (Table 5) compare favorably with the range of dry matter per cents reported for Leucama in the California Imperial Valley III

Leucaena K636 is from Coahuila Mexico and has an arboreal crown It is referred to as a new giant type by Brewbaker and is reported to be a poor seed producer 11 At Premont it produced relatively few seed pods in comparison with Leucaena K743 Perhaps this explains why K636 outproduced K 743 which apparently diverted more energy to seed production in this trial Leucaena K743 is referred to as a new fodderl fuelwood Leucaena for the highlands by Brewbaker IJ and is a cross between K8 (L leucocepha fa) and K 156 (L dilersifolia Benth)

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

4 __ _ shy ~

7- -

24 R D Kinme J T Fishfr

TABLE 3 Production Trials Southwest US SRWCP November 1986 Growth and Survival 17

Months After Field Planting

Species location Iieight (em) Stem caliper (mm) Alwage SlIriul 110 stems (1)

llepoundlll~ SD Meal SD per plum

Pnmont TX LeIlUI(IW K636 3820 714 47middot3 12middot5 26 98middot6 L((I(I11 K 7 -L 301middot1 69middot0 460 8middot3 2-0 917 Imwpi lIlha 226middot2 84-4 30() 13-4 1middot7 96middot5 illlIS eldaricu 428 17middot6 10middot2 39 10 715

Qllerclls irgillianu 111-8 351 19middot3 6-6 HI 96middot5

La Cruces NM Iilllll edllrica 473 17middot3 15middot3 6middot3 HI yg6 (lIpt(SSIIS lIriollica 12-4middot7 2Y3 31middot4 7-6 HI 96middot5 frosopl alha 215-5 101middot7 339 14middot I 1middot6 98middot6 Atriplex ClIlI(S((IIS 108middot2 16middot0 2146 34middot9 mult 96middot5

Glendah AZ Acacia millllla 42middotg 176 10middot2 39 29 97middot2 IlInIIII 1I1I00011l(CII 1620 61-5 33middot7 15-9 )-0 979 lroOII alha 2439 75middot7 31middot3 1(j() 1-8 97middot lI(1S0jl IIei 221-3 54middot3 29middot8 g 8 (HI

Stem hllght and caliper When more than one stem only largest reported = 2-4 Caliper measurements of Atriplex was not taken as the base is multi-branched and comshyplex and also hecause this is a shrub and a canopy diameter measurement is more meashyningful for relating volume 10 biomass Therefore canopy diameter in cm is reporleJ here rather than caliper

Las Cruces Nel Mexico Among the four species planted in the Production Trial in Las Cruces only Irosopis alba and Atriplex canescens reached canopy closure after 2 ycar~ Tahir 31 Prediction equations and biomass estimations were thcrcfurc determined for these species only As with Prosopis alba in Tcxa~ ci~ht was most reliably estimated by main stem volume (Table 4)

A Irip lex callescens cannot be directly compared with the three species on the basis of height and stem diameter because its shrub growth habit is dissimilar The complex multiple stem formation of A canescens is assumed to render a main stem caliper measurement less useful as an indicator of weight Therefore the average canopy diameter of Atriplex is reported in Tble 3 rather than stem caliper size For this shrub species

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

I

shy

86 Growth and Survival 17

11 J A I (rage _)1n i ( I IO _WCIll~ (uj

SI) per plalll

2) 20 l)X6 xmiddot~ 20 l)17

J~ 1-7 l)() S Jl) HI ns 6middot6 HI (rS

oJ HI WHi 7middot() HI Wr ~I I () l)X6 ~l) l)() mull

V 2-l) 1f72 l) HI l)7) HI ImiddotX 1)72 ~ ImiddotX l)3 I

ge~l reported

i multl-Iranched and comshymea~ur~-mnt i more nwshy

diamder in cm i~ reported

)n Trial in Las Cruces I canopy closure after 2 nass estimations were with Prosopis alba in

in stem volume (Tahle

I with the three species its shruh growth hahit

ion of A caIlCS((IlS is ment less useful as an

diameter of Ariplex For this shrub species

25Species screening and biomass trials in the southwest USA

TABLE 4 Second Season Prediction Equations SRWCP Southwest US November 1986

-Species location Regressiol equatioll x=~ r SyX1

Premont TX IroOpi~ ulha Lelmellu K636 LeucGeflu K 7 -+ 3

y= 22middot82 + 2middot777653 (x ) Stem volume y= - 3848 + 1789073 (x) Stem diameter y= 194-92 + 1-97521 (x) Stem volume

0middot951 0-905 (923

647-3 732H 566middot3

J I 12 12

Las Cruces NM IroWPH ulhu Alrpfe nJIlescels

y= - 463middot4 + 4639275 (x) y= -1781 +0middotQ06259(xj

Stem volume Canopy volume

0middot916 0960

1309-63 93(Hi

12 8

GlendakAZ Prosoflis ulha y= 128middot36 + 3middot237342 (x) Stein volume 0middot986 398middot4 11

Prediction equations ( Y = estimated weight in grams x = independent variablebest preshydictor [volume cm diameter mm) Px = hest predictor of biomass (stem volume canopy volume or stem diameter) I coefficient of determination 1 ~Iandlrd error of estimate = numhcr of stems destructively sampled to develop regression equation Difference in numher was due to difference in growth habit and number needed to obtain needed precision

a volume measurement of the canopy (13 r r~ h where r= average of two canopy diameters2) provided a suitable biomass predictor (Table 4)

At Las Cruces Atripex canescens produced an estimated 8middot5 plusmn3middot5 Mg ha - I year I of biomass (Table 5) which compares favorably with the maximum plant yield of 3middot5 Mg ha - I year - 1 estimated by Newton and Goodin 1-1 for that species grown near EI Paso Texas The germplasm employed in our study was the Atriplex provenance Gigas selected by NPI of Utah as a superior biomass producer The only other known biomass estimates for woody plants intensively grown in southern New Mexico are those reported for irrigated Pinus eldaricaI5 and are therefore difficult to compare directly with these results

It should be noted that the 7middot3 plusmn9middot3 Mg ha -I production of Prosopis alba at the Las Cruces site represents only 7 months of above-ground growth This is because Prosopis alba (from seed) froze back to the ground over the winter in Las Cruces By contrast Atriplex callescens did not freeze back and therefore the 12 plusmn4middot9 Mg ha - I represents the full 17 months of growth from the day of field planting

Glendae Arizona Among the four species planted only Prosopis alba reached canopy closure after 2 years (Table 3) As with P alba at the Texas and New

-~ --shy

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

-__ -- shy

~ -

26 R D Kinnse J T Fisher

TABLE 5 Second Season Biomass Estimations November 1986 Production Trials Southwest

USSRWCP

Species locution Estimated per tree

(kg)

Estimated perha

(kg IW-I)h

Estimated ha hyyear

(Mg ha - I year-I)

DI (1

fean SD Mean SD Mean SD

Pnmom TX lr(lopis alha 1middot93 134 ~8 3middot4 34 2~ 53

LtKIIIIt 1636 )76 1middot86 94 4middot5 66 3middot3 ~I

Lelcaml I 7~ 3 2middot42 167 Ml 4middot2 4middot2 29 ~l

Lu~ Crucc~ NM jmlOpi (Iha 2middot90 3middotn 7middot3 9middot3 5middot2 6middot6 ~l)

Atripex CUlHI(lIIS 4middot80 1middot98 12middot) 50 8middot5 3middot5 57

Ghnduk AZ Irtl0pI 1lh1 [80 middot28 4middot5 3middot2 3middot2 23 53

Sumple numher = 2~ (ie 6 trees per block measured) hPcr hectare esrinmte for the 17 months period is based on a spacing of 2 x2 m Total 1- ha calculation divided hy 17 months i since planted 1 multiplied hy 1

(1)1 dr~ matter conversion factor in per cent (dry weightfresh weight I x lOll

Mexico ~itcs a volume measure of the main stem was the best predictor of weight for this species at the Glendale site (Table 4) Prosopis alba hiomass production at Glendale (3middot2 plusmn 2middot3 Mg ha -I year-I) is below the yield of trees grown in the California Imperial Valley HI but the latter were irrigated regularly

DISCUSSION

The shruh Atriplex canescens has been the best overall biomass producer The estimated production of 8middot5 plusmn 3middot5 Mg ha t year- t under non-irrigated conditions in southern New Mexico certainly riyals the )-12 Mg ha - I year- I growth rates of the various hardwood tree species heing ttsted hy other projects in the SRWCP2 Coppice management of Atriplex may afford production resu1ts that surpass the overall SRWCP average In preliminary results of the SRWCP coppice management has increased productivity 20-801

Prosopis alha is the only species planted in production trials at all three sites This species froze back only at the Las Cruces site yet its hiomass yield (5-2 plusmn 6middot6 Mg ha - 1 year - I) at Las Cruces exceeds the other two sites (Tahle 5) This may indicate that fast-growing frost-sensitive

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

-bull

Iduction Trials Southwest

J)WLstillwttd ( Iw hr Har

(I~ Iw I vear I

ka1 Sf)

l4 N 53 4160 n 414middot2 2Y

06 4 l)5-2 35 57~5

) ~ =~

1 spacing of ~ x 2 m I) multiplied Iw 12 rch eight x 1110

the oe~t predictor 10k -+ i j)rosopis 0110 I Ylar - 1 J i~ oelow the Ikyl hut the latter

overall oiomas~ ha - I year - I under

) certainly rivals the wood tree species

management of the overall SRWCP

uction trials at aU Cruces site yet its

exceeds the other ing frost-sensitie

27Species screening and biomass trials in the southwest USA

plants may be efficient biomass producers in cold climates with yearly harvesting A yearly harvesting schedule may also imply closer spacing for increased biomass yields per unit of land The lower per cent in dry matter content of P alba at the Las Cruces site versus the other two sites (Table 5) may have been a result of the more rapid regrowth of this species after spring The Las Cruces plants appeared to have more succulent foliage than the plants at Glendale and Premont

The coefficients of determination of the regression equations established for Prosopis alba weights at the three sites were high (Table 4) and compared favorably with those reported for Prosopis alba by Felker et ai 16 The slopes of the three Prosopis regression lines (calcushylated separately for each site) did not differ at the 5 level of sigshynificance Data were therefore pooled across sites to increase the precision of the equation used to predict biomass of this species The pooled prediction equation for the three sites was Y= - 8598 + 3middot5 (x) with an r of 088 sample size of 34 and Sx y of 11976 This expresshysion agrees closely with that reported for South American Prosopis by Felker et al IIgt

Selection of high yielding genotypes within species can markedly increase yield L~3 1017 Felker et al1O identified and cloned a superior thornless Prosopis alba accession B2V50 This clone did not freeze to the ground at the Las Cruces site as did the P alba from seed Its superior growth at each site indicates its merit for inclusion in Phase II Production Trials Also Prosopis alba readily coppices after being harvested III

Survival of LClicaen(J K636 and K743 at all three sites (albeit different trials i indicates the winter hardiness of these lines relative to the other species tested The biomass estimates (6-4 plusmn 2middot3 Mg ha -I year-I for K636 and 4middot3 plusmn 29 Mg ha- year-I for K743) of these varieties in the Production Trials in Texas and the growth measurements in the Screenshying Trials in Arizona suggest that Leucaena varieties have potential for hioenergy production in the southwest Lelicaena has been reported to he a valuable fuelwood species having the ability to coppice readily from the stumpII-~O This species is certainly a candidate for future investigashytions in Texas and Arizona

Prosopis and Leltcaena offer an added benefit in being able to support nitrogen-fixing hacteria They are therefore capable of enhancing levels of this nutrient in southwest soils which are generally deficient in nitrogen

In summary 2-year rotations can yield 32-8-5 Mg ha -I year-I in the South-west without irrigation depending on site and species Atriplex C(JlleSCCflS growth of 8-5 plusmn 35 Mg ha -I year- 1 was particularly impressive and deserves further research emphasis in southern New

___shy --~--------

28 R D K irmse J T Fisher

Mexico The yield of this shrub and the growth of some of the tree speshycies tested in particular Leucaena and Prosopis - help support the concept that short rotation woody biomass may be feasible within the range of site conditions embraced by the study The performance of the Arriplex canesceni provenance Gigas and of the Prosopis alba clone B2V50 underscores the benefits derived from testing genotypes identified as superior through previous selection efforts

ACKNOWLEDGEMENTS

This research is performed under subcontract no 19x-89640C with Oak Ridge National Laboratory under Martin Marietta Energy Systems Inc Contract DE-AC05-g40R21400 with the US Department of Energy We gratefully acknowledge the financial support of the New Mexico Energy Research and Development Institute (NMERDI) Field studies were facilitated by the collaboration and assistance of consortium members including the lead firm International Resources Group Ltd (IRG Samuel Hale Jr and D Deardorff) New Mexico State University (Rich Phillips) Sturm Nursery (Wash Storm and N McCarn) and Mountain States Whulesale Nursery (Ron Gass) We also wish to thank Dr John T1cal NMSU and Bruce Ross (IRG) for their technical and editorial assistance

REFERENCES

I Ptr1ack R D Ranney J w Barron W E Cushman J~ H amp Trimble J L Short-rolalil)fl intensive culture for the production of entrgy feedstocks in the US A review of experimental results and remaining obstacles to commercialization Biomass 9 (1980) 145-59

) Ranney J W Trimble J L Wright L L Layton P A Perlack R D Wenzel C R Curtin D T Short rotation woody crops program Annual progre~~ report for 19X5 Oak Ridge Nat Lab Oak Ridge TN 1986

3 Burley l Wood P J amp Lines R A guide to field practice In A Mallual 011 lt(( (lml lmnllallce Research wirh Particular Reference 10 rhe Tropics cd J Burky amp P J Wood eFt Oxford UK 1976 pp 83-107

-+ Kuchler A w Potential natural vegetation A map copied by USDA Forest Service RARA II Map B) 1970

5 Brown D E (ed) Biotic communities of the American Southwest United Slate and 1exico In Oeser[ Planrs 4 Universitv of Arizona 1982

() Kirme R D amp Deardorff D D bull Short-rotation woody crop selection for hioenergy in Arizona New Mexico and Texas In Energy From Biomass Hiliding (Ill (iemric Technvlogy Base Proceeding ofthe Fourrh Technical

wr ~

11

some of the tree speshy - help support the ~e feasible within the e performance of the Prosopis alha clone

testing genotypes orts

9x-89640C with Oak Energy Systems Inc

rtment of Energy We New Mexico Energy

) Field studies vere consortium members s Group Ltd (IRG itate University l Rich Carn L and Mountain ish to thank Dr John

hnical and editorial

J H amp Trimhk J L of energy feedstocks in remaining ohstacies to

n P A Pcrlack RD crops program Annual Ridge TN 11)~()

In A 1(111( ()I~

pro 113-107 0lt11(( lO tile Tropics

copied by USDA Fore

Southwest United rizona 11)~2

oody crop selection for Energy From Biomass or tile FOllrth Teemind

Species screening and biomass trials in the sollthwest USA 29

Reliew Meeting Argonne National Laboratory Argonne IL J9H5 pp 41-1)

7 Tinus R W amp McDonald S E How to grow tree seedlings in containers in greenhouses Gen Tech Rep RM-60 Rocky Mountain Forest and Range Expt Station USDA Forest Service Fort Collins CO 1979

~ Deardorff D C amp Kirmse R D Expanded New Mexico woody biomass species trials and genetic improvement Final Technical Report NMRDI Project No 2-73-461 n 1986 Copies obtained through NMRDt Unishyversity of New Mexico Suite M 457 Washington SE Albuquerque NM H7 lOR USA

9 Kirmse R D Species screening and genetic selection at sites in Arizona New Mexico and Texas - Third annual report Submitted by International Resources Group (IRG) Washington DC to Oak Ridge National Laborashytory Oak Ridge TN 1987 (Unpublished report) IRG 1015 18th St NW Suite R02 Washington DC 20036 USA

10 Felker P Cannell G H Clark P R Osborn J F amp Nash P Biomass production of Prosopis species (mesquite) Leucaena and other leguminshyous Irees grown under heatdrought stress Forest Scibull 29 (1983) 592-606

I I Glumac E L Biomass production survival and cold tolerance of three species of Leucaena in South Texas Lellcama Research Reports 7 ( 1986) IIY-20

J 2 Brewhaker J L Leucaena Biomass Productivity Assessment Department of Horticulture University of Hawaii Honolulu (Mimeo)

13 Brewhaker J L Highland Leucaena K743 Nitrogen Fixing Tree Associashytion Waimanalo Hawaii 1985

14 Newton R J amp Goodin 1 R Unconventional arid land plants as hiomass feedstocks for energy In Plant for Arid Lands Royal Botanic Gardens Kew J YX pp 3X5-l)7

1S Fisher J 1 The forestry potential of Pinus eldarica plantations In Afghan ilpound and (hristl11as Tree $)mposiwn a proceedings New Mexico State University Las Cruces 1985 pp 7-17

16 Felker P Clark P R Osborn 1 F amp Cannell G H Biomass estimation in a young stand of mesquite (Prosopis spp) Ironwood (Olneya testola) Palo verde (Cercidium florldillm and ParkillSollia acueaw) and Leucaena 1 Leucaell leucocephala) J Range Malagebull 35 (1982) 87-9

17 Palmherg C Selection and genetic improvement of indigenous and exotic mUlti-purpose tree species for dry zones Agroforestry ywems 4 (19H6) 121-7

1X NAS Firewood Crops 511mb and Tree Species for Ellergy Productioll National Academv of Sciences Washinlrton DC 1980

Il) lAS Leucaena Promising Forage 11lliTree Crop for the Tropics 2nd edn -ational Academy Press Washinlton DC

20 NFTA Lcucaena Wood Prod~lctioll ald Use Nitrogen Fixing Tree Ao(iation Waimanalo Hawaii 1985

11

some of the tree speshy - help support the ~e feasible within the e performance of the Prosopis alha clone

testing genotypes orts

9x-89640C with Oak Energy Systems Inc

rtment of Energy We New Mexico Energy

) Field studies vere consortium members s Group Ltd (IRG itate University l Rich Carn L and Mountain ish to thank Dr John

hnical and editorial

J H amp Trimhk J L of energy feedstocks in remaining ohstacies to

n P A Pcrlack RD crops program Annual Ridge TN 11)~()

In A 1(111( ()I~

pro 113-107 0lt11(( lO tile Tropics

copied by USDA Fore

Southwest United rizona 11)~2

oody crop selection for Energy From Biomass or tile FOllrth Teemind

Species screening and biomass trials in the sollthwest USA 29

Reliew Meeting Argonne National Laboratory Argonne IL J9H5 pp 41-1)

7 Tinus R W amp McDonald S E How to grow tree seedlings in containers in greenhouses Gen Tech Rep RM-60 Rocky Mountain Forest and Range Expt Station USDA Forest Service Fort Collins CO 1979

~ Deardorff D C amp Kirmse R D Expanded New Mexico woody biomass species trials and genetic improvement Final Technical Report NMRDI Project No 2-73-461 n 1986 Copies obtained through NMRDt Unishyversity of New Mexico Suite M 457 Washington SE Albuquerque NM H7 lOR USA

9 Kirmse R D Species screening and genetic selection at sites in Arizona New Mexico and Texas - Third annual report Submitted by International Resources Group (IRG) Washington DC to Oak Ridge National Laborashytory Oak Ridge TN 1987 (Unpublished report) IRG 1015 18th St NW Suite R02 Washington DC 20036 USA

10 Felker P Cannell G H Clark P R Osborn J F amp Nash P Biomass production of Prosopis species (mesquite) Leucaena and other leguminshyous Irees grown under heatdrought stress Forest Scibull 29 (1983) 592-606

I I Glumac E L Biomass production survival and cold tolerance of three species of Leucaena in South Texas Lellcama Research Reports 7 ( 1986) IIY-20

J 2 Brewhaker J L Leucaena Biomass Productivity Assessment Department of Horticulture University of Hawaii Honolulu (Mimeo)

13 Brewhaker J L Highland Leucaena K743 Nitrogen Fixing Tree Associashytion Waimanalo Hawaii 1985

14 Newton R J amp Goodin 1 R Unconventional arid land plants as hiomass feedstocks for energy In Plant for Arid Lands Royal Botanic Gardens Kew J YX pp 3X5-l)7

1S Fisher J 1 The forestry potential of Pinus eldarica plantations In Afghan ilpound and (hristl11as Tree $)mposiwn a proceedings New Mexico State University Las Cruces 1985 pp 7-17

16 Felker P Clark P R Osborn 1 F amp Cannell G H Biomass estimation in a young stand of mesquite (Prosopis spp) Ironwood (Olneya testola) Palo verde (Cercidium florldillm and ParkillSollia acueaw) and Leucaena 1 Leucaell leucocephala) J Range Malagebull 35 (1982) 87-9

17 Palmherg C Selection and genetic improvement of indigenous and exotic mUlti-purpose tree species for dry zones Agroforestry ywems 4 (19H6) 121-7

1X NAS Firewood Crops 511mb and Tree Species for Ellergy Productioll National Academv of Sciences Washinlrton DC 1980

Il) lAS Leucaena Promising Forage 11lliTree Crop for the Tropics 2nd edn -ational Academy Press Washinlton DC

20 NFTA Lcucaena Wood Prod~lctioll ald Use Nitrogen Fixing Tree Ao(iation Waimanalo Hawaii 1985