N_TRIENT LEVELS, DISTRIBUTION AND VARIATION

IN THREE BOTTOMLAND I£%RDWOOD SPECIES

iMichael Go Messina

ABSTRACT

Utilization of the southern bottomland hardwood resource is increasing and

also the need for reliable estimates of nutrient levels, distribution and

variation on a stand basis. Nutrient data are presented for three species

of southern bottomland hardwoods° Levels of nutrient concentration by com-

ponent in a 40-year-old stand were foliage > branch bark > stem bark > branch

wood > stem wood, although this trend will vary somewhat among nutrients and

species. Variation in concentration was found to be greater within a tree

than between trees of a single species. Conversion from conventional boleharvesting to whole-tree harvesting can substantially increase nutrient re-movals from the site.

KEY WORDS: Biomass, southern hardwoods, nutrient removals,

Acer rubrum, Fraxinus _ennsylvanica, Liquidambar styraciflua

INTRODUCTION

The southern hardwood forest resource represents about forty percent of the

total commercial forest land and contains about fifty-one percent of all forestgrowing stock, making it potentially the region's most important resource.

Considerable interest is emerging regarding the inventory, silviculture andmanagement of the resource. Harvesting operations are expanding in most areas

of the Coastal Plain, yet little data exists on biomass and nutrient distri-

bution in the southern hardwoods. Coupled with the emerging interest inbottomland hardwood utilization is the increased need for wood fiber and im-

proved efficiency of harvesting. This has been the impetus behind whole-tree

utilization and short-rotation intensive culture (SRIC) forestry. Such har-

vesting and culturing systems have stimulated concern about a possible declinein soil nutrient supplies and forest productivity (Hansen and Baker, 1979;

Jorgensen, 1979; Marion, 1979). Particularly characteristic of SRIC systems

is the elevated intensity of biomass removal and decreased time periods between

harvests. Conventional tree harvesting which removes only the main portionsof the stem leaves large quantities of nutrient-rich biomass on the site. In

contrast, SRIC systems may double normal biomass removals and consist of a

series of shorter rotations which considerably promotes nutrient depletion fromthe site (Boyle, 1975).

iGraduate Research Assistant, School of Forest Resources,

North Carolina State University, Raleigh, N. C. 27650

181

It is apparent that a need has developed for reliable estimates of stand nutrient

content and distribution. White (1974) states that it is imperative that for-esters establish the rate and amount of nutrients that are removed from sites

under SR!C systems as well as whole-tree harvesting of older stands° This type

of data is being generated through an ongoing project by the North Carolina State

University, Hardwood Research Cooperative, and the Uo So Forest Service_ South-

eastern Forest Experiment Station.

A comprehensive and detailed study was designed for mixed southern, hardwoods in

the Coastal Plain, Piedmont and southern Appalachian Mountains. The study inte-

grates area plot sampling and sampling individual trees adjacent to area plots°

In this way accurate stand data are documented as well as supplementary inform-

ation necessary to complete needed diameter classes of the major species found

on the area plots.

The initial phase of the study is being conducted in the Gulf and Atlantic

_i Coastal Plains. Even-aged stands of mixed hardwoods are being sampled to quan-

tify biomass, energy yields, nutrient content and distribution, and other sub-

i_ ordinate vegetation and soils information. It is anticipated that this inform-

ation will form a comprehensive biomass, nutrient and energy content data basefor southern hardwood forests.

I

METHODS

Twenty-four circular one-tenth-acre (.04ha) plots are being distributed in

.... mixed, even-aged hardwood stands in the Atlantic and Gulf Coastal Plains.

Two replications each of four age classes (I0, 20, 40 and 60 years) are bein_

...... located in three site types: (i) Bottomland--floodplain areas adjacent to

stream drainages, predominantly loam or silt loam soils, (2) wet flats--broad,

interstream areas with poorly drained nonalluvial soils, and (3) swamps--in-

cluding peat and swamp interstream areas characterized by heavy organic matter

_._ accumulation and very poor drainage. Plots are randomly located within stands

'_ to complete this site type-age class matrix. These sites support stands whichmake up the largest proportion of commercial hardwoods in the Coastal Plain°

Presently, nineteen plots have been installed (Table i).

Soil and litter, understory vegetation, sapling trees and pulpwood and saw-

timber trees are being sampled. This paper is limited to the pulpwood and

sawtimber tree portion. Trees are felled, sectio_ned and weighed by compon-

182

Table

io

Distribution

of

191

one-tenth-acre

(°04

ha)

Coastal

Plain

biomass

plots

establishe

dby

the

N.

C.

State

Hardwood

Research

Cooperative

during

1978-79

Age

Site

Type,

Location,

Cooperator

andPlot

Number

ClassBottomland

WetFlat

SwamE

(16)SumterCo.,AL

(20)DuvalCoo,FL

American

Can

Co.

Container

Corp.

i0(18)Bertie

Co.,

NC

Georgia-Pacific

Corp.

(lO)WarrenCo.,MS

(19)TaylorCo.,FL

(15)NassauCoo,FL

International

Paper

Co

Buckeye

Cellulose

Corp

Rayonier,

Inc.

20

(13)SumterCo.,AL

AmericanCanCo.

(2)DallasCo.,AL

(9)WashingtonCo._AL

(5)CravenCoo,NC

Han_ermillPaperCo.

ScottPaperCo.

WeyerhaeuserCoo

40

(3)Southampton

Co.,

VA

(7)Tay!or

Coo,

FL

(4)Hertford

Co°_

NC

Union

Camp

Corpo

Buckeye

Cellulose

Corp

Union

CampCorpo

(1)Marion

Co.,

SC

International

Paper

Co

(ll)Wayne

Co.,

MS

(6)Craven

Co.,

NC

(12)George

Coo,

MS

Scott

Paper

Co.

Weyerhaeuser

Co.

Masonite

Corp.

60(14)EscambiaCo.,FL

(8)TayiorCoo,FL

St.RegisPaperCo.

BuckeyeCellulose

CorK°

_/Plot

17

was

established

on

the

Piedmont.

ent° Disk and foliage subsamples are then taken for nutrient content analysis

and physical property determination° Stem disks are removed at the butt,breast height _ quarter points to a 4-inch-diameter outside bark and at 2-inch-

diameter outside bark. Branch disks and foliage samples are taken from three

branches representing lower_ middle and upper crown. Individual trees of majorspecies are sampled and processed in the same manner as those within the area

plots to acquire a minimum of 3 trees/1 inch size class on a given site type°

Green and dry weights of stem and branch disks are measured after diameters i_side

and outside bark are recorded. A 60 ° wedge of clear wood is cut from sample

disks and wood and bark dried separately° Samples are ground in a Wiley mi].ito pass a 20-mesh screen and then analyzed to determine concentrations of nitro-

gen, phosphorus, potassium., calcium and magnesium.

RESULTS

Nutrient data were generated from plot 1 (Table 1), representing a 40-year-old,mixed red river bottom hardwood stand situated on a well-drained loam soil on

the South Carolina Coastal Plain. The plot was sampled in August of 1978.

The three major species investigated were green ash (Fraxinus pen n_syl_vai_Aci}Marsh.), sweetgum (Liquidambar styraciflua L.) and red maple (Acer rubrum L.).

Several trends occurred consistently in the nutrient concentrations in a2t threespecies :

i. Nutrient concentrations were higher in bark than in the wood for all elements,

particularly for calcium.

2. Bark nutrient concentrations varied less among bole positions than woodnutrient concentrations.

3. There was generally an increase in nutrient concentrations in stem wood

with bole height.

4. Magnesium and phosphorus varied least of all elements with bole height inboth wood and bark.

5. There was generally a decrease in concentration with increasing branch diameter

<i_i in both branch bark and wood except in the case of calcium in branch bark

}%_} where the opposite trend occurred.

6. The order in which nutrients occurred in bole bark was Ca > N > K > Mg > P.

Green Ash. Nutrient concentrations followed the aforementioned general trends

(Table 2). Nitrogen in the stem wood showed the most increase with height andmagnesium the least. The order in which nutrients occur in stem wood is

N = £ > Ca > P > Mg. For foliage this trend is N > K > Ca > Mg = Po

Sweet&umo Elemental concentration trends (Table 3) were similar to those in

green ash. An exception is the order in which nutrients occur in the stem wood:

Ca > N > K > Mg > P and foliage: N > Ca > K > Hg > P.

mllll III

Table

2.

Average

percent

concentration

of

five

elements

by

sampling

position

for

8green

ash

trees

from

40-year-old

stand

Percent

Concentration

SamplingPosition

NP

KCa

Mg

Leaves

2.43(.261)*

.24(.014)

1.00(.151)

o84(o155)

.25(.037)

Branches

<.5"

(wood

&bark)

.56(.125)

.16(.040)

.37(.092)

.41(.135)

.08(o010)

Branches

.5"-2"

bark

.52(.052)

.04(.008)

.33(.056)

.90(o161)

.10(.012)

wood

.28(.087)

.09(.035)

.19(.028)

.12(_046)

.03(.012)

Branches

2"-4"

bark

.43(.050)

.04(.006)

.30(.041)

1.08(.136)

.09(.008)

wood

.18(.053)

.07(.028)

.17(.021)

.10(.045)

.03(.007)

Branches>4"

0o

bark

38(032)

04(005)

.28(.067)

1.25(.268)

.09(.004)

(._

"•

••

.o

wood

.14(.022)

.04(.012)

.15(.014)

09(051)

.02(.003)

Stem

Wood

butt

.12(.022)

.02(.007)

.12(.033)

.07(.011)

.02(.003)

dbh

.11(.016)

.02(.009)

.12(.018)

.08(.038)

°02(.003)

height

.10(.009)

.02(.007)

.12(.017)

.06(o010)

.02(.001)

½height

.11(.062)

.02(.009)

.12(.018)

.06(.009)

.01(.002)

4/4

height

.12(.030)

.03(.008)

.15(.017)

.07(.009)

.02(.002)

dob

.15(.021)

.05(.008)

.16(.014)

.07(.022)

.02(.004)

2"dob

.21(.040)

.08(.024)

.18(.019)

.10(.025)

.03(.008)

Stem

Bark

butt

.49(.094)

.03(.006)

.27(.038)

1.75(.385)

.09(.019)

dbh

.42(.065)

.04(.009)

.27(.061)

1.47(.359)

.08(.016)

height

.37(.040)

.03(.005)

.26(.069)

1.41(.467)

.08(.010)

½height

.37(.053)

.03(.008)

.24(.084)

i.19(.144)

.08(.010)

3/4

height

.40(.023)

.03(.006)

.25(.078)

1.28(.244)

.08(.009)

4"Hob

.43(.053)

.04(.008)

.31(.100)

1.21(.265)

o09(.015)

2"dob

.47(.060)

.05(.007)

.37(.069)

.85(.153)

.09(.0]0)

•Numbers

in

parentheses

are

standard

deviations.

Table

3._%yeraz$e])ercent

conc

entr

atio

nof

five

elem

ents

bv_....

....

.sa

n_Dl

ingi

___t_z:

....

....

___°°siti°n

for

7sweet

sum

trees

from

a40-_,ear-oid

stand

Percent

Concentration

Sampling

Position

NP

KCa

Hg

Leaves

I_70(.282)*

.14(.017)

.55(.087)

.86(_122)

°32(°022)

Branches

<.5"

.30(.043)

.04(.008)

.18(.041)

,56(.199)

.07(.010)

(wood

&bark)

Branches

.5"

-2"

bark

.43(.070)

.04(.006)

.23(.020)

1.98(.296)

.13(.039)

wood

.14(.032)

.03(.005)

.11(.013)

.19(.029)

.03(.007)

Branches

2"

-4"

bark

o35(.043)

.04(.009)

.34(o142)

1,69(.330)

.11(.020)

wood

.11(.03)

.03(.012)

_i0(.019)

.09(.010)

.03(.009)

COO_

Stem

Wood

butt

.08(.028)

.02(.008)

,09(.039)

.11(.004)

.03(.008)

dbh

°08(.020)

.01(.005)

.08(.027)

°i0(.011)

.03(.010)

height

.08(.025)

.01(.005)

.07(,016)

.i0(.011)

.03(.009)

½height

.08(.023)

,01(.005)

.07(.010)

,09(.012)

°02(°007)

3/4

height

.08(.021)

.01(.003)

.07(.009)

.10(.045)

.03(.005)

4"dob

o09(.080)

.02(.008)

.09(.025)

o09(_023)

.03(.009)

2"dob

o10(.018)

.02(°003)

.10(.029)

o10(.024)

o03(.01)

Stem

Bark

butt

.40(.123)

.05(.013)

.37(.109)

2°78(.702)

.14(o040)

dbh

.36(.086)

.04(.010)

.30(.092)

2o48(1o067)

,14(.041)

height

.32(.078)

°04(.006)

.27(°058)

1.95(.879)

.15(.032)

½height

.29(.079)

.04(.008)

.27(.064)

1,53(.652)

.15(.043)

3/4

height

.30(.076)

.04(.006)

.29(.062)

1.71(o609)

o15(o042)

4"

dob

.30(.048)

.04(.008)

°26(°080)

1o53(o406)

o13(o024)

2'_dob

,36(.049)

.04(.006)

.26(.038)

Io58(_40)

o14(o04)

*Numbers

in

parentheses

are

standard

deviations.

Red Maple° Generally_ nutrient concentration trends (Table 4) followed !!

those cited for all species. The hierarchy of nutrient concentrations was_for stem wood: N = K > Ca > P = Mg and for foliage: N > K > Ca > Mg > P. _

Magnesium and phosphorus did not vary in concentration with bole height and °

wereequaltoeachother.

Elemental content on a biomass percentage in green ash (Table 5) effectively

illustrates relationships found to occur in all three species.

Table 5. _ weight and nutrient content of sreen ash expressed as percentase

ofabovegroundtotals i

Component Wt. N P K Ca Mg

BoleWood 72.6 39.0 42.9 54.9 23.5 37.8

Bole Bark 7.1 14.0 6.3 i0.4 43.7 20.1

Bole Subtotal 79.7 53.0 49.2 65.3 67.2 57.9

TopWood 1.5 2.5 5.2 2.8 i.i 2.3

TopBark 0.3 1.0 0.5 0.9 1.9 1.3Branches 17.0 24.1 34.4 21.3 23.5 24.7

Foliage i.5 19.4 I0.7 9.7 6.3 13.8

Top Subtotal 20.3 47.0 50.8 34.7 32.8 42.1 0

Data such as that contained in Table 5 can be useful when assessing extent of

nutrient removal associated with harvesting systems. Approximately 80% of the

aboveground biomass is contained in the bole of green ash. A harvest of total

aboveground material would increase biomass removal by 25% over conventionalharvesting removal. However, such a harvest would increase removal of nutrients

by the following percentages: nitrogen, 89; phosphorus, 103; potassium, 53_calcium, 49; and magnesium, 73.

It is stressed that the above estimates are valid only for green ash growing

on a Coastal Plain bottomland site or some very similar situation. Time of

harvesting is also a factor governing application of these estimates due to

the varying rates of mobilization of nutrients at different times of the year.

The values given estimate nutrient removal from the site in biomass and do not

necessarily show true system losses, particularly for nitrogen. Primary agents

of nitrogen loss are leaching, denitrification and harvest removal. Rauscher

(1980) found that the greater the litter amount on the site after a harvest,

the greater the loss of nitrogen sustained by the system. A total tree harvest

will produce less litter than a bole harvest, resulting in less nitrogen lossdue to leaching and denitrification. Therefore, the accelerated removal of

nitrogen in a whole-tree harvest is partially offset by the fact that lessbiomass remains on the site to mineralize nitrogen. Yet total loss of nitrogen

is greater in a whole-tree harvest than in a conventional harvest.

187

il>i:i¸i¸¸

posi

tion

Table

4Average

percent

concentration

of

five

elements

by

samnling

_'....

for

5red

maple

trees

Jrcm

a40-year-old

stand

Percent

Concentration

SamplingPosition

NP

KCa

Mg

..

.0_

)Leaves

1,93(,196)*

.17(.023)

,62(,062)

59(109)

22(.

'9

Branches

.5"

(wood

&bark)

.46(.176)

,06(.031)

.20(.058)

.30(,051)

,04(.016)

Branches

,5"-

2"

bark

.59(.038)

,06(.017)

.25(.045)

,78(,120)

,07(,013)

woo

d.1

4(.

00

8)

.02

(.0

05

).1

0(.

02

8)

.13

(.0

18

).0

2(.

00

9)

Bra

nch

es2"

-4"

bark

.43(.015)

.07(.008)

.29(.009)

,81(.1315)

.06(,011)

co

wood

12(017)

.02(.002)

.08(,013)

.08(011)

01(.000)

CO

•"

Stem

Wood

bu

tt.1

1(.

008)

.02(.

008)

.13(.

049)

.10

(.0

37

).0

2(.

00

5)

dbh

.10(

.011

).0

2(.0

02)

.11(

.022

).1

1(.0

22)

.02(

.002

)

½height

.10(,014)

.02(.004)

.ii(.021)

.09(.021)

,02(,005)

½height

,10(.017)

.02(.004)

.10(,020)

,08(.008)

.02(,005)

3/4

height

.10(.024)

.02(.006)

,ii(.024)

.09(.022)

,02(,003)

4"dob

.11(o019)

.02(.003)

.09(.010)

.07(.010)

,02(,003)

2"dob

.15(.041)

.02(,003)

.ii(.041)

,08(.016)

,02(.003)

Stem

Bark

butt

.55(.074)

.07(.010)

.36(.067)

i.21(.312)

,08(.017)

dbh

.56(.062)

.06(.010)

.33(.097)

1,01(,235)

,08(,012)

height

.55(.083)

.06(.008)

.32(.081)

°96(.172)

°07(o011)

½height

.56(.078)

.05(,012)

,28(.083)

,86(.i67)

,06(,012)

3/4

height

.55(.062)

.07(.033)

.32(,077)

,76(,196)

,06(,011)

4"dob

.57(.051)

,06(.014)

.32(,073)

,68(,211)

°06(°007)

2"gob

.70(.123)

o07(.019)

.34(.087)

.58(o106)

o07(,010)

*Numbers

in

parentheses

are

standard

deviations°

SUMMARY AND CONCLUSIONS

Data concerning nutrient levels and distribution in the southern bottomtand

hardwoods can be a valuable asset in determining managerial policy of tl_is

important resource. Interest is increasing in assessing the implication of

whole-tree harvesting on the ability of bottomland sites to provide contin<_ed

high levels of productivity. Paralleling the increase in biomass removal is an

even greater increase in nutrient removal due to harvesting the nutrient-rich

foliage and branches that remain on the site in a conventional harvest.

Sampling of a 40-year-old bottomland hardwood stand indicates that nutrient

levels were variable among the species but patterns of distribution within the

species were similar. Elemental concentrations varied more within a tree than

among trees of a particular species.

Work is continuing on a variety of other bottomland sites in anticipation of a

comprehensive biomass and nutrient content data base for the southern bottomlandhardwood forests.

LITERATURE CITED

Boyle, J. R. 1975. Nutrients in relation to intensive culture of forest crops.

Iowa State J. Res. 49:297-303.

_lansen, E. A. and J. B. Baker. 1979. Biomass and nutrient removal in short-

rotation intensively cultured plantations, pp. 130 - 151. I_nnProc.,

impact of Intensive Harvesting on Forest Nutrient Cycling. S.U.N.Y.

Jorgensen, J. R. 1979. Effect of intensive harvesting on nutrient supply and

sustained productivity, pp. 212 - 230. In Proc., Impact of Intensive

Harvesting on Forest Nutrient Cycling. S.U.N.Y.

Marion, G.M. 1979. Biomass and nutrient removal in long-rotation stands.

pp. 98 - ii0. In Proc., Impact of Intensive Harvesting on Forest Nutrient

Cycling. S.U.N.Y.

Rauscher, H. M. 1980. An analysis of nitrogen removal from southern Appa-

lachian oak ecosystems by harvesting. Ph. D. Dissertation. Virginia

Polytechnic institute and State Univ., Blacksburg, Va. 145 pp.

White, E. H. 1974. Whole-tree harvesting depletes soil nutrients.Can. J. For. Res. 4:530-535.

189