Note No. 82 1978 ISSN 0384-2002

Drag' Scarification Trials in Lodgepole Pine Logging Slash in the Nelson Forest District of British Columbia by C.F. Thompson

63409097 !British Ctolumbia 11 8 CMF :Ministry' Of RES R N $2 I y 3 8

Forests

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DRAG SCARIFICATION TRIALS IN LODGEPOLE PINE LOGGING SLASH IN THE NELSON FOREST DISTRICT

OF BRITISH COLUMBIA

by

C . F . THOMPSON

Research Note # 82

E. P. 714

Forest Service Research Division Ministry of Forests Province of British Columbia Legislative Buildings Victoria, B.C. V8V 1x5

B r i t i s h Columbia Cata loguing in Publ icat ion Data

Thompson, Christopher Frank, 1943- . p i n e l o g g i n g s l a s h i n t h e N e l s o n F o r e s t D i s t r i c t o f B r i t i s h Columbia.

Drag s c a r i f i c a t i o n t r i a l s i n l o d g e p o l e

(Research note - B r i t i s h Columbia Fores t Serv ice ; #82 I S S N 0384-2002)

"E.P. 714.'! B ib l iography : p. I S B N 0-771 9-8029-9

1 . Fores t reproduc t ion - B r i t i s h Columbia - Kootenay d i s t r i c t . 2. Lodge-pole p ine. 3. Slash (Logging). 1 . B r i t i s h Columbia. Forest Serv ice. Research Div is ion. I I . T i t l e . I l l . Ser ies : B r i t i sh Co lumb ia . Forest Service. Research note ; no. 82.

SD409.T45 634.956'0971144

TABLE OF CONTENTS

ABSTRACT AIMS LOCATIONS SURVEYS

1. Seedbed 2. Cone Supply 3 . Seed Quality 4. Regeneration

FACTORS INFLUENCING THE EFFECTIVENESS OF SCARIFICATION 1. Cone and Seed Supply 2. Age of Slash and Season of Scarification 3. Degree of Disturbance 4. Season of Logging

FACTORS INFLUENCING THE COST OF SCARIFICATION 1. Slash Loading 2. Leave Trees 3. Topography 4. Area Size 5. Stumps

DISCUSSION AND CONCLUSIONS REFERENCES

LIST OF TABLES Table 1 - Locations Scarified Table 2 - Percentage Distribution of Seedbed Table 3 - Cone Distribution Table 4 - Cone and Seed Quality (Wuho Creek) Table 5 - Regeneration Surveys

LIST OF FIGURES Figure 1 - Effect of Disturbance on Stocking Figure 2 - Variation of Time with Area and Slope

1 1 4

4 4 4

7 7

10 10 10 10 11 11 11 11 11 13

8 9

ii

ABSTRACT

The f i r s t f i ve yea r s ' progress of six cut-over lodgepole pine areas that were d r a g scar i f ied i n 1972 and 1973 is reported. tach area was examined for seedbed, seed source and the resultant fourth year regeneration. The degree of disturbance, cone supply and the age of s lash were found t o be the most important s i l v i - cultural factors influencing the success of scar i f icat ion. Given an adequate cone supply and fresh logging slash, 60% distribution o f mineral so i l plus disturbed seedbed was found t o produce a satisfactory stocking level of 50% on a milacre basis. I f scar i - f ica t ion i s delayed until after the summer heat, an additional 20 t o 25% disturbance would be required t o produce similar stocking levels. Factors influencing the cost o f scar i f icat ion are a lso discussed,

1.

DRAG SCARIFICATlON TRIALS I N LODGEPOLE PINE LOGGING SLASH i N THE

NELSON FOREST DISTRICT OF B R I T l S H COLUMBIA

When t h e N e l s o n F o r e s t D i s t r i c t a c q u i r e d i t s f i r s t c k i n d r a g s c a r i f i e r i n l a t e 1971, the cur ren t t rea tment fo r cu t -over a reas o f lodgepo le p ine was t o e i t h e r l e a v e them and hope fo r na tu ra l regenera t i on , o r t o b road- cas t bu rn i f the s lash appeared to p resent a hazard. About the same time, doubts were be ing expressed about the e f fect iveness o f the current pract ice i n p roduc ing sa t i s fac to r i l y na tu ra l l y res tocked a reas . It was hoped t h a t t he d rag sca r i f i e r wou ld be a v a l i d s i 1 v i cu I t u r a l a1 t e r n a t i v e t o t h e u s u a l t reatment.

Th is research no te i s an account o f t h e p r o g r e s s o f t h e f i r s t s i x l o c a - t i o n s t o b e d r a g s c a r i f i e d i n t h e N e l s o n F o r e s t D i s t r i c t d u r i n g 1972 and e a r l y 1973.

AIMS

The p r i m a r y a i m o f t h i s p r o j e c t was t o t e s t t h e e f f e c t i v e n e s s o f t h e c h a i n d r a g s c a r i f i e r i n i n d u c i n g n a t u r a l r e g e n e r a t i o n o f l o d g e p o l e p i n e .

A secondary aim was t o examine t h e r e l a t i o n s h i p s between t h e n a t u r e o f t h e c lea rcu t and t he e f fec t i veness o f t he sca r i f i e r .

LOCATIONS

t a c h l o c a t i o n s c a r i f i e d ( T a b l e I ) was s e l e c t e d b y U i s t r i c t S i l v i c u I t u r a l s t a f f and by Ranger s ta f f . Be fo re t rea tmen t , a p o r t i o n o f t h e a r e a (usua l ly about two hectares) was se lec ted and marked as a c o n t r o l . 1-he s e l e c t i o n o f t h e c o n t r o l was o f ten t empered by cons ide ra t i ons o f e f f i c i en t machine operation. I n a l l cases, the control i s cons ide red t o be s a t i s - f a c t o r i l y r e p r e s e n t a t i v e o f t h e t r e a t e d a r e a s .

SURVEYS

1 . ' Seedbed

The seedbed surveys (Table 2) were c a r r i e d o u t u s i n g described by Uecie and Fraser ( 1960) a I though the c r seedbed c l a s s i f i c a t i o n s were d i f f e ren t .

the procedures i t e r i a f o r t h e

P e r c e n t a g e d i s t r i b u t i o n o f seedbed was determined using about 200 m i lac re p l o t s ( 1 0 0 i n c o n t r o l s ) d i s t r i b u t e d a t p r e d e t e r m i n e d i n t e r v a l s t h r o u g h the t reated area. I n each p l o t , seedbed was t a l l i e d i n t h e o r d e r : M i n e r a l , Disturbed, Kotten Wood, Undisturbed and NO Seedbed, w i t h a,t l e a s t one s q u a r e f o o t o f a seedbed be ing requ i red be fo re a p l o t c o u l d be t a l l i e d t o t h a t seedbed. lhus a p l o t w o u l d be t a l l i e d as "d is tu rbed" i f it conta ined less than one square foo t o f m inera l so i l , bu t more than one square foo t of d is tu rbed. It would be immaterial how much o f t h e o t h e r seedbeds were present.

2.

Table 1

Locations Scarified

LOCATION

Wuho Creek Elk Creek Goathide Creek Kettle River - A

- B

- c - D

Beaverfoot River White River

PRIME MOVER

D8 D8 D8** JD44 0 TJ404 D7 D6 TD2 4 D8

13.8 24.4 21 .0

18.8 19.2 19.2 4.8

28.0 14 .0

COST* ($/ha)

52.8 70.3

100.2

22.8 34.4 58.8 71.3 52.0*** 75.0"""

* Scarification Cost only, excludes fireguards, repairs, transportation, etc. , these costs range from 69% (Elk Creek) to 93% (Goathide Creek) of the total cost per hectare.

** Many small areas combined.

*** Estimated costs, they are probably "all found".

NB Mention of Trade names is for ident i f icat ion purposes only; i t should not be construed as an endorsement.

The basic scarifier consists of four chains attached behind two triangular boats (two chains per boat). Each boat (with chains) can be used independently as a t Kettle River, or combined behind a third larger boat to make a four chain drag as was used a t the remaining areas.

3 .

a, cn

N

a,

v)

\D

In

rn d

a3

0 rl

a3

cn hl

4.

The different seedbeds are as follows:

a .

b .

C .

d .

e .

Mineral--areas from which the duff layers have been removed e i ther by scar i f icat ion or d u r i n g the course of logging.

Disturbed--areas where the duff layers have been broken u p . Mineral so i l may be vis ible , b u t in minor qua l i t i es ; often inc I udes a mixing w i t h minera I soil t o a greater or lesser extent.

Rotten Wood--well decayed and flattened - usually sparse in pine stands.

Undisturbed--the duff layer i s essent ia l iy una1 tered. tquipment tracks may be vis ible , b u t the surface is unbroken. No mineral soi I i s v i s ib l e .

No Seedbed--Hocks , open water, logs, stumps and slash piles too deep for seed.lings to emerge through.

The only permanent markers used i n a l l surveys were the s t a r t of each survey line. No plot centres were marked.

2 . Cone Supply

In every fourth milacre plot, a one-square-foot p l o t was marked a t the s ta r t of the p l o t along the line of t ravel . The number of cones i n this p l o t were counted. Unly old fu I ly open cones were ignored.

3. Seed Qua I i ty

The two cones closest to each mi lacre plot centre were collected a t Wuho Creek. These cones were s t r a t i f i e d by degree of weathering, extracted and the resulting seeds germinated (Table 4 ) .

4. Kegenerati on

Up to three regeneration surveys were made using milacre plots a t the same spacing as the seedbed survey (Table 5 ) . W i t h one exception, regeneration surveys d i d n o t s t a r t u n t i I the t h i r d year af ter scar i f icat ion. An arbitrary three, one-year seed1 i n g s or one, two-year seedling were regarded as s a t i s - factory stocking for one plot . Many "stocked" plots were in fact "over- stocked" . FHCTURS lNFLUENCING THE EFFECTIVENtSS UF SLARlFILATlON

Most factors are inter-related to a considerable extent. For the sake of simplicity however, they wil I be discussed separately.

5 .

Table 3

Cone Distribution

LOCATION

lriuho Creek Light, old slash Heavy, old slash Heavy, green slash

Elk Creek Goathide Creek Kettle River - A

- B "

- L - D

Beaverfoot River White River

NOMBER OF CONES PER m2 Scarified Control

1 7 36 13

1 2 11 22 19 25 9 22 21

53 24

21 18 32

44 1 4

Table 4

Cone and Seed Quality (Mho Creek)

Degree of No. of Germination No. of No. of Viable Seeds Weathering Seeds Percent Viable Seeds Cones Per Cone __

0-25% 2,522 66.0 1 ,664 .5 218 7.6 25-50% 1 ,190 66.8 794.9 104 7.6 50-100% 6,568 56.4 3,704.4 1090 3.4

TOTAL, 10,280 6,163.8 1412 4.4

-. ".

Table 5

Area ____

Wuho Creek Light, old slash Light, fresh slash' Heavy, old slash Heavy, fresh slash Heavy, old slashc

Elk Creek Control

Goathide Creek Control

Kettle River A B C D Control

Beaverfoot River Control

White River Control

6.

Regeneration Surveys

Date Date Regeneration Survey ( fa1 1 Logged Scarified Percent stocked (by milacre) (approx. 1 1975 1976 1977

7- 71 10- 71 7-71

10- 71 9- 70

1-71

2-72

4-72

11-72

10- 72

6-72 46 41" 45 64 30

7-72

8-72

9-72

14

60 12

22 29 23 14 13

6-73

7-73 63 10

46 nil** 57 74 36

16 6

13 36 21 6 14

26 15

55 10

30 63 40 26 30

51 11

* 41% is lodgepole pine, with all species is 70% ** destroyed by slashburn escape. c control

7

1 . Cone and Seed Supply

Scarification reduced the number of cones present from a weighted average of 31.1 cones per m 2 on a l l cont ro l areas t o 17 .2 cones per m2 on the treated areas. Distribution was irregular, with up t o 37 cones being recorded on one square-foot plot. The overall distribution of cones was n o t drast ical ly altered by scar i f icat ion, with an average of 71 percent of the control plots containing one or more cones and 66 percent of the scarified plots containing one or more cones.

Only on area D a t Kettle River, i s i t f e l t t h a the cone supply may have been 1 imi t ing. There, the cone count ( 9 per m 5 ) was the minimum suggested by C1 ark ( 1971) as being necessary for successful restocking. The cone distribution percent was less t h a n 50% (48 .5%) . Theoretical calculations suggest t h a t t h i s should s t i l l have been adequate f o r restocking. This2 does n o t appear t o be the case. The second lowest cone count ( 1 1 per m , 55% cone dis t r ibut ion) a t Goathide Creek, was obviously n o t limiting t o regenerati on.

Cones were collected only a t Wuho Creek, and the seeds were extracted and tested. The number of viable seeds per cone (Table 4 ) i s low compared with the average of 24 seeds per cone with 80% viability reported by Clark (1974) . Of in te res t i s the relatively uniform germination capacity of the seeds from different aged cones (as assessed by the degree of weathering). The lower yield from the older cones i s possibly a resul t of misjudging the i r serotiny. I t is possible t h a t some of them had previously opened, especially as some cones wi 11 open a t lower temperatures than originally reported (Perry and Lotan 1977)

All the areas scarified were believed t o have a h i g h degree of cone serotiny. This factor was n o t formally monitored, b u t a l l the locations were in areas where a generally closed cone habit predominates.

If the lowest cone count from Table 3 and the average seed count from Table 4 are used a figure of 396,000 viable seeds per hectare i s obtained. I t i s f e l t t h a t this should be adequate t o produce 1,200 seedlinas per hectare. This would be a r a t io of 330 viable seeds t o 1 established seedling.

2 . Age of Slash and Season of Scarification

A temperature of 45 t o 55OC was original ly reported as being required t o break the resin bond of serotinous cones before the seed can be re1 eased (Clements 1910) . This temperature can be achieved near ground level with a i r temperatures of a t l eas t 2 7 O C (Crossley 1956). Thus slash t h a t has n o t been t h r o u g h the heat of summer before i t i s s c a r i f i e d has a larger quantity of seed available for regeneration. The older slash has already released some seed t h a t i s probably buried by the scarification. Two areas a t Wuho Creek and four areas a t Kettle River had been t h r o u g h the heat of summer and thus had probably lo s t a portion of their available seeds. This i s reflected i n considerably 1 ower stocking levels when compared wi t h other areas o f comparable disturbance. Of these areas, the area a t Wuho Creek t h a t exceeded 50% stocking had double the cone count of i t s l e s s successful neighbour. This area also had heavier slash. I t is quite possible

8.

FIGURE 1 EFFECT OF DISTURBANCE ON STOCKING

+' I / 1 I 1 I 2 0 40 6 0 80 100

P E R C E N T D l S T R J 6 U T l O N OF MINERAL PLUS D I S T U R B E D S E E D B E D

Stocking

Cont ro l Areas Fresh Slash Old Slash

3 r d year 4 t h year

0

0

A

9.

FIGURE 2 VARIATION OF TIME WITH AREA AND SLOPE

7 -

6 -

5 -

n v) CY 3 4- 0 L Y

w 2 3 -

2-

1-

A 20-25

/ ’ / -

/ 1’ I$’

Y + I 2

A R E A (HECTARES)

I 3

GOATHIDE CREEK 1972

10.

t h a t scar i f icat ion lowered the level of the slash such that more cones were exposed t o the temperature required to open the cones. More seeds would thus become available. A t Kettle River, only one of the four areas exceeded 50% stocking; this one area had a greater degree of disturbance than i t s neighbours: bo th the cone count and the slash l o a d i n g a t Kettle River were very uniform, w i t h the exception o f area D . A t E l k Creek, over a year had elapsed between l o g g i n g and scar i f icat ion; this is ref lected i n the low stocking leve7 a t that location. The absence of sui table seedbed hindered regeneration o f the control i n sp i te of a more than adequate cone SUPPlY.

3. Degree of Disturbance

Lodgepole Pine regeneration was growing primarily on areas of mineral so or on areas where mineral soil and d u f f had been mixed ("Disturbed"). Figure 1 shows the strong dependence of stocking on the degree of dis- turbance as measured by the percentage distribution o f mineral soil plus seedbed, once the basic difference between ''fresh" and "old" slash i s recogn i zed.

i l

disturbed

For the purposes o f Figure 1 , a l l control areas were regarded as ''fresh" since no dis turbance occurred a f t e r l o g g i n g .

Figure 1 shows that fa i lure to scar i fy promptly a f t e r l o g g i n g can r e su l t i n a reduction of the potential stocking level after fou r years of about 20%, for a given degree of disturbance. In fresh slash, w i t h an adequate cone supply, about 60% d i s t r i b u t i o n o f mineral soi l plus disturbed seedbed i s required t o achieve 50% stocking (on a milacre basis) or '1,200 stems per hectare after fou r years. This is the current m i n i m u m acceptable administrative stocking s tandard for lodgepole pine i n British Columbia (B.C.F.S. n . d . ) . To achieve a similar stocking level of lodgepole pine i n slash that has been through a summer before scarification, the disturbance percentage must be raised t o about 80 to 85%.

4. Season of Logging

The l ikely resul ts o f logging i n the snow free season are lower stumps and a greater degree of disturbance, the former permitting easier machine move- ment, the latter possibly making scar i f icat ion unnecessary, i f topography i s such that a sk id ' t ra i l system i s unnecessary.

The aim of scarification i n these projects was t o produce 100% coverage by the drag . This i s re f lec ted i n the relatively small range of the f i n a l disturbance, when compared w i t h the quite large range of disturbance i n the control area. Thus the major influence of i n i t i a l degree of disturbance would be t o determine whether or not scarification was required.

FACTORS INFLUENCING THE COST OF SCARIFICATION

1. Slash Loading

Heavy slash requires a larger machine t o pull the drag scarifier. A t the two areas dragged by wheeled skidders a t Kettle River, the slash loading was of l i t t l e impediment t o the prime movers. In sp i te of the fact that

11.

the skidders were pulling only two chains, and thus required double the number of trips to produce 100% coverage, the cost o f these operations was low compared t o areas where the slash required a larger prime mover such as Wuho Creek or Beaverfoot River.

2 . Leave Trees

Block C a t e t t l e River was relatively heavily stocked w i t h leave trees. I t was f e l t r that without the leave trees, the full scarifier combination ( 4 chains) could have been used, ha1 v i n g the number of trips required and thus reducing the cost considerably.

3 . Topography

Steep terrain i s a major influence on the cost of scar i f icat ion due to bo th the requirement for a larger prime mover to combat the steep slopes and to the increased time spent manoeuvering on slopes. Figure 2 summarizes the experience a t Goathide Creek where a variety of slopes were experienced. I t i s f e l t t h a t 20 to 25% slopes are the maximum that should be tackled, and then only under exceptional circumstances. The operator a t Goathide Creek found that the only way he could get effective scarification on the steeper pitches was to scar i fy downhill. The u p h i l l leg was effectively wasted.

The relat ively h i g h cost a t White River can be s imilar i ly a t t r ibuted to short steep pitches w i t h i n the scarification area.

4. Area Size

Figure 2 also shows that in areas smaller t h a n about 4 hectares, the machine spends too much time manoeuvering and too 1 i t t l e time actually scarifying. This was a considerable contribution t o the cost of scar i f icat ion a t Goathide Creek.

5 . Stumps

High stumps from winter l o g g i n g were a contributor t o the h i g h c o s t a t Elk Creek. Similarly a t Kettle River, although not too h i g h for the other prime movers used, the stumps were too h i g h fo r a D6; again producing disproportionately h i g h costs.

DISCUSSION AND CONCLUSIONS

W i t h i n the limitations o f the above-mentioned influences on bo th the s i lv i - cultural effectiveness and the cost of drag scarification, the two most important factors t o consider are the time lapse between logging and scar i - f ication and the degree of disturbance achieved by scar i f icat ion. On the basis of the data assembled i n this project , the effects of these two factors

1 . Pistak, W.O. 1972, Pers. comm.

12.

appear t o be independent of s i t e ! The locations monitored are widely separated geographically, representing four sub-zones i n two biogeo- climatic zones ( U t z i g 1977); and so i l s range from coarse textured outwash materials t o s i l t y loams. About the.only unifying features are the generally f l a t t o undulating topography of the majority of the areas, and the fact that lodgepole pine i s one of the more appropriate species for a l l the locations. These overall differences appear t o have had l i t t l e influence on the trends of the results shown i n Figure 1 .

The stocking levels used are the regeneration plot data from four years af ter the f i rs t regenerat ion is es t imated t o have occurred. These are NOT the final stocking levels. Regeneration i s continuing as evidenced by new germinants found a t each regeneration survey. Smithers (1961) reported that 70 percent of the regeneration occurs i n the f i r s t f ive years, w i t h a further 21 percent i n the next five years. As a resu l t , many o f the areas presently called "satisfactorily stocked" will become over-stocked for optimum growth. In f ac t , due t o the irregular d i stri bu- t ion, some are already i n that si tuation. I t should be remembered tha t the 50% stocking level used i s a minimum administratively acceptable level. Quite possibly, those areas that are presently marginally or even sub- marginally acceptable will eventually be close t o optimally stocked. Only time will prove that. An arbitrary termination of this project was required i n o rder t h a t the results reported would be s t i l l meaningful.

Because of the continuing nature of lodgepole pine regeneration one should be cautious of premature condemnation of apparently unsuccessful scari- f icat ion projects . Firs t ly , there is of ten a delay of several years before regeneration occurs, the precise cause being unknown. Delayed seed release and a form of seed dormancy may b o t h be involved. Secondly, regeneration i n lodgepole pine i s a process that continues for up to 15 years . T h u s , af ter f ive years , we can say that drag scar i f ica t ion i s a valid silvicultural technique t o achieve administratively acceptable stocking levels i n lodgepole pine, provided the seed source is adequate and scar i - f i ca t ion i s prompt. Knowledge of the ultimate stocking of these areas wi l l not be available for another 10 years, by which time juvenile spacing will probably be required i n many o f the areas. Since most of the areas treated are topographically appropriate, machine spacing should be quite feasible.

13.

References:

B. C . F. S . , n .d . Reforestation Manual, Instructions t o Forest Officers i n Reforestation. B . C . Forest Service, Reforestation Division.

Clark, M.B. , 1971 Working Plan EP 698, Effect of Cutting Method, Slash Disposal, Treatment, Seedbed Preparation and Cone Habit on Natural Regeneration of Lodgepole Pine. B.C.F.S. Res. Div. Unpubl .

Clark, M.B. , 1974 Effect of Cutting Method, Slash Disposal, Treatment, Seedbed Preparation and Cone Hab i t on Natural Regeneration of Lodgepole Pine i n the South-Central Interior of British Columbia. B.C.F.S., Res. Note 67.

Decie, T.P . and Fraser, A . R . , 1960, Miscellaneous Notes on Scarification Trials, Prince George Distr ic t 1956 to 1959, B.C.F.S. Res. Note 36,

Clements, F.E. , 1910, The Life History of Lodgepole Pine Burn Forests, U 5 . D . A . For. Serv. Bull. 79.

Crossley, D.I . , 1959, The Effect of Crown Cover and Slash Density on the Release of Seed from S1 ash Borne Lodgepol e Pine Cones, Canada Dept. N . A. & N . R. , For. Br. , For. Res. Div. , Tech. Note 41.

Perry, D . A . , and Lotan, J.E., 1977, Opening Temperatures in Serotinous Cones of Lodgepole Pine, U.S.F.S. Research Note INT-228.

Smithers, L . A . , 1961, Lodgepole Pine in Alberta, Canada Dept. For. Bull. 127.

Utzig, G . and MacDonald, D . , 1977, Guide for Tree Species Selection In the Nelson Forest District, First Approximation, B.C.F .S . , Ne1 son Distr ic t .