* B R I T I S H C O L U M B I A F O R E S T S E R V I C E .

4 No. 37 VICTORIA, B.C., CANADA 1963

Ilirect 3eeding bxperiments with

White Spruce, Alpine Fir, Douglas Fir, and Lodgepole Pine in the Central Interior of British Columbia

BY

A. E. PROCHNAU Reread Divrjton

FOREST SERVICE DEPARTMENT OF LANDS, FORESTS, AND WATER RESOURCES

The subject matter of t h i s Research Note has

been repor ted in g rea te r de t a i l as a t h e s i s ,

ent i t led, "Direct Seeding of White Spruce, Alpine

F i r , Douglas f i r and Lodgepole pine i n t h e C e n t r a l

I n t e r i o r of B r i t i s h Columbia", submitted by t h e

a u t h o r i n p a r t i a l f u l f i l l m e n t of the requirements

for the degree of Master of Forestry, University

of Washington, 1961.

..

. -

CONTENTS

INTRODUCTION 1

DESCRIPTION OF STUDY AREA 1

Location "" 1

C limat e 1

Topography 2

So i l s . 2

The Forest 2

a ) general 2 b ) s i t e t y p e s 2 c) species composition

~ 3 d) s tand condi t ions 3

EXPERIMENTS .__- 3

RESULTS " 6

Rodents "_ 6

Humus Seedbeds __. 6

S i t e , Seedbed, Species and Stand Condition 7

Prepared Seedbeds on Upland S i t e s 8

Time of Sowing 9

Height Growth of Seedlings 9

Natural Regeneration 12

DISCUSSION OF RESULTS 12

Seedbeds - 13

Stand Conditions and Vegetat ion Si te Types 15

Climate and Time of Seeding 1%

Rodents 20

Other Factors 20

SUMMARY AND CONCLUSIONS 20

REFERENCES.- 22

INTRODUCTION

Sixteen mill ion acres of forest land are logged or burned-over, or bear non-commercial f o r e s t s i n t h e i n t e r i o r of the Province of B r i t i s h Columbia (B.C .F.S ., 1957). Interior logging accounts for 44"per cent of the provincial cut , and, of t h i s ; 35 pe r cen t i s spruce species (B.C .F .S., 1961). Immediate r e fo res t a t ion o f t h i s spec ie s i s es sen t i a l , i f t h i s i n t e n s i t y of cut i s t o be sustained.

Some progress i s being made in regenera t ing cu t -over fores t l and i n t h e i n t e r i o r . I n t h e p e r i o d 1952-1961, 7,800 acres were planted (not a l l with spruce) and during 1961, 4,120 acres were s c a r i f i e d t o provide sa t i s fac tory seedbeds for regenera t ion (B.C .F .S ., 1961). But t he re a r e s t i l l vas t a r eas i n need o f a r t i f i c i a l r egene ra t ion . For example, within a 100 mile radius of Prince George, 400,000 acres are not satisfactorily restocked (Silburn, 1960). Consequently there i s an important need t o develop various methods o f r e fo res t a t ion .

The purpose of t h i s work i s t o e v a l u a t e t h e p o s s i b i l i t i e s of obtaining regeneration by na tu ra l means and by direct seeding of t ree spec ies o f the spruce-a lp ine f i r fo res t s in the cen t ra l in te r ior of Br i t i sh Columbia.

DESCRIPTION OF STUDY AREA

Location

The s tudy area i s located on the Aleza Lake Forest Experiment Station, about 40 miles northeast of Prince George ( l a t i t u d e 54'5 ' , longitude 122'10').

"" Climate

The climate i s a complex o f a l t e rna t ing con t inen ta l and maritime inf luences . A s a resu l t , win ters a re co ld wi th heavy snowfall and summers are short , cool , and wet wi th per iodic hot , d ry spe l l s .

TABLE 1. Monthly and Annual Mean Temperatures a t Aleza Lake f o r t h e Years 1953 t o 1957

40

+ "

c

Juri .I J u l .I Aug .I Sep .I Oct .I Nov I Dec . I Annual 23

36 21

36 16

33 2

37 22

39

- 2 -

TABLE 2 . Monthly and Annual P rec ip i t a t ion at Aleza Lake f o r t h e Years 1953 t o 1957

Year

4.13 2.73 0.86 1.69 4.41 2.84 1.74 1.17 5.25 5.10 5.74 1955

5.02 3.66 3.51 2.22 2.38 3.38 2.26 1.54 1.28 3.71 1.87 1954

2.38 3.11 3.61 3.03 2.22 3.07 1.48 1.15 1.93 2.89 8.00 1953

Nov. Oct . Sep . J u l . ' Aug . Jun. May Apr . Feb . IMar . Jan .

1956 3.66 3.90 2.10 2.33 1.24 4.25 0.20 1.07 2.55 6.90 2.27

1957 4.36 1.99 0.88 4.70 3.06 4.34 1 .03 '1-32 1.97 3.39 1.89 t . - " ~~ ~

Source : B. C . Department of Agriculture 1953-7.

Topography

Land conf igura t ion var ies f rom leve l to undula t ing t o r o l l i n g .

Elevations range from 2140 t o 2320 f e e t above sea l eve l .

S o i l s

Soi l s a re der ived from g lac i a l l ake depos i t s and g l a c i a l outwash (Farstad and Laird 1954). They cons is t of the Pineview, Aleza and Bednest i ser ies der ived from s t r a t i f i e d g l a c i a l l a k e c l a y and s i l t s , and the Eena ser ies , der ived from s t r a t i f i e d g l a c i a l outwash f ine sands . They are podsol ized so i l s wi th some g le iza t ion occur r ing a t varying depths depending upon subsoil drainage . The Forest

(a) General

The fo re s t has been c l a s s i f i ed as the Montane Transi t ion sect ion of t he Montane Forest Region, because of the scattered occurrence of Douglas fir (Rowe, 1959).

( b ) S i t e Types

Four major s i t e - types were recognised for th i s s tudy , namely (a) Cornus-Moss (C-M), (b) Aralia Dryopteris (A-D), ( c ) Oplopanax (0) , and (d ) Equisetum-Sphagnum (E-S). T h i s s t r a t i f i c a t i o n was based on an eco log ica l c l a s s i f i ca t ion of t h e f o r e s t by Arlidge and later reported by Illingworth and Arlidge (1960).

- 3 -

(c) Species Composition

The f o r e s t i s composed of a mixture of white spruce (Picea lauca (Moen. ) Voss .) and a lp ine f i r (Abies l as iocarpa (Hook. ) Nutt ,"

sca t te red whi te b i rch (Betu la papyr i fe ra Marsh.), trembling aspen (Populus tremuloides Michx. ) and i n t e r i o r Douglas f ir (Pseudotsuga menziesii (Mirb .) Franco). A few lodgepole pine (Pinus contorta Doug. v a r . l a t i f o l i a Ehgelm. ) may also occur on upland s i t e s . Black spruce (Picea mariana (Mill.) B.S .P. ) and lodgepole pine are found on bog s i t e s and around margins of lakes. Black cottonwood (Populus t r ichocarpa T & B. ) i s commonly found on a l l u v i a l s o i l s .

(d) Stand Conditions

U n t i l r e c e n t l y s e l e c t i v e f e l l i n g , f i r s t by diameter limit and l a t e r by marking, was the general logging pract ice . A dense res idual s tand is t y p i c a l of post-logging conditions. Even following the current system of s t r i p c l e a r - c u t t i n g o r patch c lear-cut t ing with seed blocks there i s a s i g n i f i c a n t amount of shade from re s idua l cu l l - t r ees , po le s and advanced regeneration. The only clear-cut areas, i n the s t r i c t sense, are those i n which the r e s idua l t r ee s have been fe l led and slash burned . In th i s study, three 'stand condition' environments were recognized as f a c t o r s a f fec t ing regenera t ion . (1) v i r g i n , mature s t and (na tu ra l ) ; ( 2 ) logged t o a diameter limit (logged); and (3 ) logged and burned (burned).

EXPERIMENTS

I n 1953, 48 p l o t s were e s t ab l i shed i n the described s i t e types and selected s tand condi t ions. The choice of plot locations was designed to expedi te remeasurement by s taying c lose to an e ight-mile trail which connected t h e s i t e s and stands of i n t e re s t . Wi th in each p lo t , su f - f ic ien t seedspots were located annual ly to accommodate several , individual experiments and t h e i r placement was de l ibera te , des igned to avoid t rees , stumps, logs, slash, and rocks. The species, seedbed and rodent control treatments of each experiment were assigned at random to the seedspot loca- t ions .

Seedbed treatments were defined as:

Humus; undisturbed humus and ground vegetation,

Mineral; humus l a y e r removed t o expose mineral soil , ground vegetation removed from immediate surroundings,

Mineral deep; 1/2 i n c h t o two inches minera l so i l removed t o B horizon, ground vegetation removed,

Mixed; humus and mineral s o i l c u t t o a s i x i n c h t o e i g h t inch depth and mixed; ground vegetation removed,

Mound; a mound s i x i n c h e s t o e i g h t i n c h e s above the spr ing high-water level on wet E-S s i t e only.

Seedspots varied i n s i z e frsm 12 inches square t o 12 by 18 inches.

- 4 -

Rodent control treatments included:

(i) Screened; eight inches by eight inches by two inches, four mesh per inch hardware c lo th fas tened to so i l wi th sof t i ron wire hooks.

(ii ) Unscreened;

(iii) Covered; 1/4 inch of top so i l used as seed-cover,

( i v ) Uncovered.

Seed was of loca l o r ig in wi th the except ion of tha t for one seedlot (alpine f i r ) used i n 1953. After adjustment on the basis of germination t e s t s , and dependent on quant i t ies ava i lab le , es t imated numbers of viable seeds (25, 35 or 5 0 ) were sown per spot . In the 1953 seedings the low q u a l i t y a l p i n e f i r s e e d was s t r a t i f i e d f o r 28 days before use, but the spruce was n o t s t r a t i f i e d . I n a l l other experiments, spring-sown seed was s t r a t i f i e d f o r 1 4 days .

Factor and treatments under test have been summarised as a s e r i e s of s i x experiments (Table 3 ) .

Records of a l l experiments including germination, mortality and survival counts were made at one t o t h r e e week intervals throughout the f i r s t growing season. Spring and f a l l counts of survival were made f o r t h r e e more growing seasons. Measures of seedling height and vigour were made each f a l l .

- 5 -

a3 dc cu

dc n

rl

a 2 aJ aJ k 0 cn

a a

aJ c aJ c

.ri k k

.d k k

rl

T ? o u t

Y w Y w

rl

cu dc dc dc cu cu

rl cu M d

- 6 -

RESULTS ( - ~ The de ta i l ed ana lys i s of each facet of each t r i a l has been reported

by the author (Prochnau 1961). In t h i s r e sea rch no te , t he r e su l t s have been assembled b r i e f l y by topics rather than experiments. Averages are used t o i l l u s t r a t e major findings. Emphasis i s placed on th i rd yea r s u r v i v a l s t a t i s t i c s which perhaps represent the end of t h e c r i t i c a l g e r - mination and establishment period and the beginning of stand development. Necessarily, such procedure sacrifices the authority lent by reporting detailed analyses and some minor poin ts and i n t e r a c t i o n s which might i n - f luence in te rpre ta t ion have been l o s t .

A l l su rv iva l s t a t i s t i c s a r e exp res sed as percentages of viable seeds sown.

Rodents

Two experiments ( 5 and 6 ) were concerned wi th roden t con t ro l t e s t s . The survival of seedl ings af ter three seasons i s shown as a percentage of viable seeds sown for experiment 5 (Table 4 ) .

TABLE 4. Effect of Rodent Control on Survival Percentages.

Screened Unscreened Species spots spots

Spruce 5 Aipine f ir Douglas f i r Lodgepole pine

31 36 13

14 3

I 3 I I

Screened seedspots gave significantly higher survival percentages than unscreened spots for a l l four species. Covering seed with 1 /4 inch of s o i l had no s ign i f i can t bene f i t , e i t he r i n p ro t ec t ing s eed aga ins t rodents on unscreened spots o r increasing numbers of seedlings on screened spots.

I n experiment 6, the unscreened spots were a complete f a i l u r e as compared to an average surv iva l of 28 per cent on protected spots. ,

A l l f u r t h e r r e s u l t s a r e b a s e d on screened seedspots with no s o i l - cover . Humus Seedbeds

Experiments 1 t o 4 included humus seedbed as treatments. With two exceptions, these seedbeds were f a i l u r e s f o r a l l species on a l l s i t e s and under a l l stand conditions. The surv iva l o f f i r s t year seedl ings averaged only 3 per cent compared t o 26 per cent for mineral or mixed seedbeds.

- 7 -

One exception occurred on upland s i t e s under the na tura l s tand in 1953, where s u r v i v a l a f t e r one year averaged 11 per cent. Another, on an equisetum site, burned, happened during the wetter than average year 1954, when surv iva l was 21 per cent of viable seeds sown.

Three years a f t e r sowing surv iva l on a l l humus seedbeds was n i l .

S i t e , Seedbed, Species, and Stand Condition

Experiments 1, 3 , 5 , and 6 were cond,ucted on a r t i f i c i a l l y - c r e a t e d seedbeds on upland s i t e s (C-My A-D, and 0 ) . Minor differences between these s i tes were observed i n germination and survival of seedl ings during the f i rs t year . However, by t h e end of t h e t h i r d growing-season s i t e differences had disappeared for any given species, seedbed, and stand con- dition combination and data from up land s i t e s a r e t he re fo re combined.

Experiments 2 and 4 were car r ied ou t in the E-S s i t e t y p e . Shallow organic muck depos i t s , up t o 12 inches deep overlie mottled, mineral sub- soils. Prepared seedbeds similar t o upland si tes are not possible because of surface water in the spring. Seeding was therefore car r ied ou t on mounds, b u i l t up s ix inches to e ight inches above high water l e v e l .

The r e s u l t s of these experiments indicate the effect of s i te and associated kinds of prepared seedbed upon the su rv iva l of seedlings of various species (Table 5 ) .

TABLE 5 . Effect of Site and Associated Type of Prepared Seedbed on Survival.

Experiment S i t e Seedbed Date sown Survival a t end of year

Species Stand Condition

Spruce Natural

Burned Logged

Alpine f i r Natural Logged Burned

Douglas fir Natural Logged Burned

Pine Natural

Burned IJQ3ged

1 Up land

Mineral & Mixed

1954 1957

2 32 20

6 52 29

3 25 39

0 11 21

2 E-S

Mound

1954 1957

1 3 4

7 13 47

2 10 6

0 2 7

+- Up land

1957

- 8 -

The complete f a i l u r e of a lpine f i r i n experiments 3 and 4 i s believed due t o t h e u s e of low qual i ty seed of foreign or igin. In a l l other cases, the seed was of good q u a l i t y and l o c a l o r i g i n .

(

After detailed analyses of these experiments (Prochnau, 1961), it i s noted:

The g e n e r a l f a i l u r e of a l l species under the natural s tand was pre- ceded by f i r s t season survivals as high as under other stand conditions, i .e. 40-70 per cent for spruce and a lpine f i re , 10-40 per cen t for Douglas fir and pine on i n d i v i d u a l s i t e s and seedbeds. Most mortal i ty occurred during the f i rs t winter season followed by l i t t l e m o r t a l i t y i n second and th i rd years . Therefore , the resu l t s in Table 5 a r e considered to represent es tabl ished seedl ings.

The i n t e r a c t i o n of species with the two stand conditions, logged and burned, i s s ignif icant in experiments 1 and 2 . On upland s i tes , spruce and alpine f i r su rv ived bes t i n t he environment of a logged s tand and sat isfactor i ly under the more open logged condition. The more i n t o l e r a n t Douglas f i r and pine showed preference for the burned environment. On mounds i n swamp s i t e s , sowing o f a l p i n e f i r was a success under burned conditions.

Prepared Seedbeds on Upland S i t e s

In general , the mineral seedbeds provided a medium which was b e t t e r for germination and f i r s t y e a r s u r v i v a l t h a n mixed seedbeds. In experiment 1, ( under natural s tand condi t ions, the differences disappeared as mortal i ty reducgd survivors t o t h e amounts recorded af ter three years (Table 5 ) .

Under logged o r burned conditions, however, the mineral seed beds continued t o show t h i r d year survivals considerably in excess of those on mixed mineral/humus seedbeds (Table 6).

TABLE 6 . Third Year Survival by Species and Seedbed, Experiment 1, Upland S i tes , Logged and Burned Stand Conditions.

Species Seedbed Mineral Mixed

Spruce Alpine fir Douglas f i r Pine

29

11 21 27 37 23 58 23

I n experiment 3, the treatment, deep mineral seedbed, was an immediate failure under natural stand conditions because the depressions collected water and accumulating l i t t e r smothered the seedlings. No differences per- s i s t e d between deep mineral, mineral, or mixed seedbeds a t the end of th ree years under logged and burned conditions.

- 9 -

!

Time of Sowinq

Experiment 6 was concerned with studying the influence of date of seeding on seed germination and seedling survival. The r e s u l t s a r e first season survival percentages of viable seeds sown (Table 7 ) . They are averages of mineral and mixed seedbeds f o r two upland s i tes , A-D and 0 .

TABLE 7 . F i r s t Year Survival Following Various Dates of Sowing.

Date of Sowing

Species June 28 June 2 Nov. 2 Sept . 3 Stand Condition 1956 1956 195 5 195 5

Spruce

32 43 39 20 Burned 44 5 1 19 24 Logged 56 24 16 9 Natural

D. Fir Natura l 9 9

14 49 34 23 Burned

11 16 b 3 F d 21 28 35 38

The main e f f e c t s of date, stand condition, and species; and the species-date , s tand-date interact ions were a l l s ign i f icant . Bes t sowing dates are apparent ly unique for each species and stand condition.

Height Growth of Seedlings

Analysis of height growth was r e s t r i c t e d t o t h o s e c l a s s i f i c a t i o n s which showed s a t i s f a c t o r y t h i r d y e a r s u r v i v a l s t a t i s t i c s :

sites - A-D, C-M, 0 seedbeds - mineral, mixed stand conditions - logged, burned

Early height growth did not differ among the th ree up land s i tes .

Interact ions of species with s tand condi t ion and with seedbed were s i g n i f i c a n t . The Douglas f i r showed b e t t e r growth on the logged than on the burned a rea ; the p ine d id be t te r on the burned than the logged, and spruce and alpine f i r showed no stand condition preferences. Both spruce and Douglas f i r were s i g n i f i c a n t l y t a l l e r on the mixed than on mineral seedbeds and the a lpine f ir and lodgepole pine showed no seedbed preferences.

- 10 -

1 - View of Burned Area i n F a l l 1959. Several natural white spruce seedlings a re in foreground.

TABLE 8. Height (cms . ) at End of W e e Growing Seasons by Species for S tand Condi+,ions and Seedbeds.

Species

Douglas f i r

Alpine f ir

White spruce

bdgepole pine

T

5 -33

4.30

3 -98

2 -79

:0: I ndi t ion Burned

r 4 -77

4.16

3 -55

3 a33

See Mineral

4.58

4.22

3.42

3 -09

oed Mixed

5 -50

4.26

4.18

3.18

A t t he end of the th i rd year , spec ies d i f fe rences were a l l s ign i f i can t w i t h a ranking of Douglas f i r , a lp ine fir, spruce and pine, from greatest t o least heights (Table 8 ) .

- 11 - Seeding rat es were de l ibe ra t e ly heavy in these experiments ar,d ,

subsequent to the successfu l es tab l i shment of numerous-seedlings on some . spots , a problem of overstocking and a changed ranking in he ight -va lues i s evident s ix years after sowing (Table 9 and Pla t e s 2 and 3 ) .

2 - Spot-sown Douglas f i r seed- l i ngs , 6 years old, and white spruce, 7 years old.

3 - Six-year-old lodgepole pine seedl ings with natural white spruce seedl ings ( lef t and r igh t foreground) .

TABU3 9. Stocking and Height o f 6 Year Old Seedlings.

Range i n s e e d l i n g s Range i n h e i g h t Species (cms .> per spot

Pine

Douglas f ir

Alpine f ir

Spruce

1 - 14 2 - 34 1 - 21

1 - 14

9 - 122 5 - 33

6 - 20

5 - 17

- 12 - Natural Regeneration

Natural regeneration was checked i n d e t a i l t o e l i m i n a t e i t s e f f e c t from di rec t seeding resu l t s . In fac t , seed c rops were f a i lu re s du r ing t h e sowing years ( fewer than f ive seeds per square foot) and no ad jus t - ments were considered necessary.

I n 1957, however, following a good seed crop of spruce (185 seeds per square foot under natural stand conditions) establishment of spruce was excel lent . Natural regenerat ion on a l l burned plots and on one-half t he na tu ra l s t and p lo t s a r e summarized i n Table 10 by time since seedbeds were prepared. Results are expressed in percentage of seedspots supporting one o r more seedlings and extreme range in numbers of seedlings per spot.

TABLE 10. Natural Stocking of Spruce Following Good Seed Crop.

4 ear._old spots }*d I Range

.: 3 year old spo t s Stand 1 Stocked I Range

T Condition I I no. seedlings j 1.0 .seedlings

Natural

1 - 3 5 1 - 3 7 Burned

1 - 38 64 1 - 18 72

1 year old spots - Stocked

-

97

16

Range no. seedlings

1 - 43

1 - 2

The burned plots were two t o t e n c h a i n s from the nearest seed trees and a t a n unknown dis tance from a seed source located in a favourable d i rec t ion . This might account for the lower resul ts on the burned area. It i s apparent that the 3- and 4-year-old spots were less receptive than the year-old ones.

DISCUSSION OF RESULTS

I n a review of t h e l i t e r a t u r e on direct seeding, Westman (1958) s t a t e s that there has been a tremendous d i v e r s i t y of r e s u l t s i n a n e q u a l l y tremendous number of d i r ec t s eed ing p ro j ec t s . Westman wr i t e s fu r the r tha t a l t h o u g h l i t t l e o r no d i rec t seeding has been carried out on a successful la rge opera t iona l sca le un t i l the last few years, there has been a wide- spread recogni t ion by foresters of the great potent ia l i t ies of di rect seed- ing fo r cheap , l a rge-sca le re fores ta t ion p ro jec ts .

Westman (1958) s t a t e s a l s o t h a t numerous authors have emphasized the hazardous nature of direct seeding associated wi th three main f a c t o r s a f fec t ing t ree seedl ing es tab l i shment : (1) seedbed conditions; (2) the population of rodents o r other seed-destroying animals; and ( 3 ) moisture and temperature conditions during and immediately following the germina- t i on pe r iod . The r e s u l t s of the project being reported generally confirm these conclusions, and the discussion to fol low w i l l expand these main f a c t o r s and o the r f ac to r s which influenced seedling establishment a t Aleza Lake .

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Seedbeds

A general review of European, American and Canadian l i t e r a t u r e on the influence of seedbed on regenerat ion in spruce forests , leaves the impression that the problem i s similar throughout the range of spruce. The undisturbed humus l aye r s o f t he so i l which develop under spruce stands are sometimes t o o deep to a l low root pene t ra t ion of seedl ings, and the surface layers tend t o dry out rapidly in periods of dry weather, l imiting germination of seed and early survival of seedlings. It i s general ly accepted that mineral soi l seedbeds are bet ter media than humus seedbeds for germination of seed and early survival of seedlings, mainly because of a higher water-holding capacity.

I n o r d e r t o c o n t r i b u t e t h e o r e t i c a l background t o t h e problem of accumulation of deep humus i n spruce fores t s , b r ie f re fe rence w i l l be made t o a number of excel lent and interest ing papers . Wright (1955), in d i scuss ing the gene t ics and ecology of the spruces of the world, comments t h a t a l l species (except S i t k a spruce (Picea si tchensis (Bong.) Carr.) a r e found a t e i ther h igh l a t i t udes or h igh a l t i t udes , meaning in reg ions o f re la t ive ly d ry , cool c l imate .

Although most of the species occupy mesophytic s i tes (adequate moisture for good t ree g rowth) , the re la t ive ly d ry , cool c l imate c rea tes surface moisture and temperature conditions which slow the processes of decomposition of humus, giving r ise to the accumulation of deep raw humus. Lutz and Chandler (1946) emphasize that low temperatures and a deficiency o r excess of moisture tend to increase the depth of l i t t e r by i n h i b i t i n g i t s decomposition.

Handley (1954), i n rev iewing the l i t e ra ture on mull and mor humus f o r m a t i o n i n r e l a t i o n t o f o r e s t s o i l s , s t r e s s e s t h a t , of t h e s o i l - forming factors , vegetat ion has the greatest inf luence on the kind and depth of humus layer accumulation. Handley w r i t e s t h a t as a working general izat ion it can be said that in temperate c l imates , coniferous, ericaceous, and i n some instances, beech vegetation, i s l i k e l y to be assoc ia ted wi th the raw mor humus, whereas other broad-leaved trees and shrubs and herbaceous g round f lo ra a re l ike ly to be assoc ia ted with the more ac t ive ly decomposing mull humus. Braun (1950), i n commenting on the d i s t r ibu t ion of mul l and mor i n r e l a t i o n t o v e g e t a t i o n i n t h e f o r e s t s of the Uni ted S ta tes , s ta tes tha t whi le mul l commonly develops under mixed hardwood stands supporting a rich herbaceous vegetation, mor corn- monly develops under coni fe rs , be ing par t icu lar ly charac te r i s t ic of the northern coniferous or s p r u c e - f i r f o r e s t .

From a survey of na tura l regenera t ion on cut-over and burned- over l ands in Canada (eas t o f the Rocky Mountains ) , Candy (1951) con- cludes that regeneration following any disturbance i s much l e s s abundant west of Lake Supe r io r t han i n t he ea s t . Candy gives two probable reasons for t h i s : (1) a lack of moisture i n t h e west as compared t o t h e e a s t ; )2 ) a slower decomposition of the dry ground l i t t e r which proved i n many instances a handicap t o the establishment of coniferous

- 14 - reproduction. Candy mentions that the Prair ie Provinces average an annual p rec ip i ta t ion o f l ess than 20 inches, as compared t o over 40 inches for the Maritime Provinces. Place (1955), i n d i scuss ing t h i ck - ness of humus layers across Canada, notes the increasing depth of l i t t e r i n f o r e s t s of spruce and f ir as one t r a v e l s west i n t o d r i e r , o r n o r t h in to coo le r , c l ima tes . In t he abundant r a i n f a l l o f New Brunswick, t h e thickness of t h e humus layers under red spruce (Picea rubens Sarg.), white spruce, and balsam fir (Abies balsamea (L.)l.)upland s i t e s averages about two inches and seldom exceeds three or four inches. In the d r i e r c l ima te of Alberta, the humus is commonly th ree t o e igh t i nches thick under white spruce (Holman, 197).

A t Aleza Lake, depth of humus on upland s i t e s i s probably not limit- ing to the es tabl ishment of white spruce, a lpine f i r , Douglas f ir and lodgepole pine. Place (1955) s t a t e s that i n New Brunswick, i f t h e humus exceeds two inches, it t ends t o become l imit ing for spruce (white , red and black spruce) and when t h i c k e r t h a n t h r e e i n c h e s , f o r f i r (balsam f i r ) . A t Aleza Lake, because of a r e l a t i v e l y wet climate (average annual p r e c i p i t a t i o n : 36 inches ) and a r e l a t ive ly l uxur i an t ground vegetation, humus layers seldom accumulate t o more than two i n c h e s i n t o t a l d e p t h . On the natural s tand experimental p lots of t h i s study, depth of humus v a r i e d l i t t l e on var ious vegetat ion s i te types, a l though degree of de- composition did vary because of d i f f e rences i n ground vegetation and moisture conditions.

The 0 s i t e ( t h e w e t t e s t of the upland s i tes , with t h e g r e a t e s t number of species and density of ground p lan ts ) has the most a c t i v e l y decomposing humus (F-layer, one-half to one inch in depth; H-layer, one- h a l f t o one i n c h i n d e p t h ) . The A-D s i t e i s in te rmedia te in ra te o f humus decomposition, and the C-M s i t e ( t h e d r i e s t of the up land s i tes , with the smallest number of species and density of ground plants) has t h e l e a s t a c t i v e l y decomposing humus (F-layer , one-half to one and one- half inches in depth; H-layer , zero to one-half inch i n depth) . Humus layers on the logged area and the burned area (a l i gh t bu rn ) were similar in dep th t o t hose o f t he na tu ra l s t and .

Barr (1930) , working a t A l e z a Lake, demonstrated the importance of soi l moisture to the es tabl ishment of spruce reproduct ion and the con- siderable advantages of exposed mineral soil over undisturbed r a w humus seedbeds. Barr concluded t h a t humus seedbeds limit the avai lable moisture and restr ic t germinat ion. Smith (1955) , working with Engelmann spruce and alpine f ir at Bolean Lake i n the Southern Inter ior of Bri t ish Columbia, confirmed Barr's findings. Place (1955), in discussing seedbed prefer- ances of spruce (white, red and black spruce) and f ir (balsam f i r ) , s t a t e s t h a t many undisturbed natural seedbeds have a s u p e r f i c i a l l a y e r which dr ies ra ther quickly and, i f t he r a in fa l l du r ing June and Ju ly i s low, l i t t l e r e g e n e r a t i o n w i l l become established even on normally good seedbeds. Reviews o f t he s i l v i ca l cha rac t e r i s t i c s of white spruce (Nienstaedt, 1957), Engelmann spruce (Alexander, 1958), a lp ine f ir (Alexander, 1958), Douglas fir (Isaac and Dimock 11, 1958), and lodgepole pine (Tackle, 1959), a l s o emphasize the significance of seedbed moisture to the regeneration of these species. Generally speaking, undisturbed humus seedbeds dry out rapidly in pe r iods of dry weather, making them poorer seedbeds than mineral soil seedbeds.

- 1 5 -

The r e s u l t s of this s tudy confirm that the preparat ion of mineral s o i l seedbeds i s e s s e n t i a l t o good establishment of white spruce, alpine f i r e , Douglas fir, and lodgepole pine. On the logged and burned areas, seeding on humus seedbeds was a complete f a i l u r e f o r a l l species sown, i n bo th t he s l i gh t ly d r i e r t han ave rage growing season of 1953 and the s l ight ly wet ter than average growing season of 1954. However, it i s i n t e r e s t i n g t o n o t e t h e fair too good first-growing-season survival of spruce, alpine fir, and Douglas fir on humus seedbeds i n t h e n a t u r a l s tand. Whether these f i rs t -season seedl ings could be saved by removal of the s tand in the winter fol lowir ig seedl ing es tabl ishment i s not c e r t a i n . I f th is were p o s s i b l e , t h i s would c o n t r i b u t e t o t h e argument for pre- logging scar i f icat ion (Decie and Fraser , 1960) , in which logging would also be carried out in the winter following f irst-growing-season establishment, in order to save the regeneration which established on scar i f ied seedbeds .

O f the two types of scar i f ied seedbeds involved in th i s pro jec t , the mineral seedbed proved, generally speaking, t o be the bes t i n r ega rd t o s u r v i v a l of seedlings, whereas the mixed seedbed proved t o be the best in regard to height growth. In the 1954 sowings, the mineral seedbed gave s ignif icant ly higher seedl ing survival than the mixed seedbed. It appeared that the mixed seedbed dried out more quickly and easily than the mineral seedbed because of i t s loose nature , resul t ing from the mixing of humus and mineral s o i l i n i t s prepara t ion . In the 1953 and 1955-56 sowings, however, there was no s i g n i f i c a n t d i f f e r e n c e i n numbers of seedlings surviving on the two types.

S t a t i s t i c a l a n a l y s i s of height data of the 1954 sowings showed t h a t three-year-old white spruce and Douglas f ir seedlings were s i g n i f i c a n t l y t a l l e r on mixed than on mineral seedbeds, although seedbed was not s i g n i f i c a n t i n r e g a r d t o h e i g h t growth f o r a l p i n e f i r and lodgepole pine. LeBarrow (1944) found that black spruce seedlings grew b e t t e r on burned, scar i f ied duff and undis turbed forest f loor than on mine ra l so i l . Stoeckeler (1945) reported that red pine (Pinus resinosa A i t . ) and black spruce were 50 p e r c e n t t a l l e r on d i sked so i l s than in fur rows severa l yea r s a f t e r p l an t ing and a t t r i b u t e d t h i s t o t h e n u t r i e n t s i n t h e humus.

Stand Conditions and Vegetation Site Types

The r e su l t s o f t h i s p ro j ec t i nd ica t e that t h e main influence of s tand condi t ions and vegetat ion s i te types on regeneration i s through vary ing l igh t condi t ions , wi th an ind i rec t e f fec t from temperature and moisture conditions. Bates (1917 and 1925) compares t h e r e l a t i v e l i g h t requirements of seedl ings of species involved in this project . Al though comparatively deep shade improved ear ly surv iva l , Engelmann spruce w i l l germinate and become e s t a b l i s h e d i n a l l i n t e n s i t i e s o f l i g h t found i n nature . It can make b e t t e r use of low l i g h t i n t e n s i t i e s t h a n e i t h e r l o d g e - pole pine o r i n t e r i o r Douglas f ir , but when grown wi th more shade-enduring species such as a l p i n e f i r , t h e n e t e f f e c t of deep shade favors the f i r . Baker (1949) rates white and Engelmann spruces as t o l e r a n t i n t h e i r a b i l i t y t o endure shade. Alpine f i r i s r a t e d as very to le ran t , Douglas f i r as in te rmedia te in to le rance to shade , and lodgepole pine as i n t o l e r a n t .

- 16 - LeBarron and Jamison (1953) have shown that about 50 per cent

shade i s d e s i r a b l e i n t h e f i r s t t h r e e growing seasons for best germina- t i o n and survival of Engelmann spruce and alpine f ir . Although com- paratively heavy shade i s d e s i r a b l e f o r t h e i n i t i a l e s t a b l i s h m e n t of bo th spec ies , the ne t e f fec t i s more favourable t o f i r t h a n t o spruce. Spruce seedl ings can withstand exposure to l ight a l i t t l e b e t t e r t h a n f ir . Smith (1955) found t h a t e a r l y growth of Ehgelmann spruce and a lp ine f ir was bes t on mineral or burned seedbeds which received 70 per cent of fu l l sun l igh t . Tack le (1959) s t a t e s t ha t t he bes t ge rmina t ion of lodgepole pine occurs i n f u l l s h l i g h t and on minera l so i l o r d i s turbed duff that i s f r e e of competing vegetation.

With t h e above s i lv i ca l i n fo rma t ion i n mind, it would appear from t h e r e s u l t s of t h i s study that the logged area (about 10 years o ld) presented the best l ight condi t ions for good gemina t ion and e a r l y survival of spruce and alpine f ir , whereas the burned area (about 10 years o ld) p resented the bes t l igh t condi t ions f o r good germination and ear ly surv iva l of Douglas f ir and lodgepole pine. Results of the 1954 sowings showed the above, although stand condition was n o t s i g n i f i c a n t i n the 1953 sowings of spruce and alpine f i r . However, the 1955-56 sowings aga in ver i f ied tha t spruce preferred the logged area, whereas Douglas f ir preferred the burned area f o r germination and early survival.

S t a t i s t i c a l a n a l y s i s of height data of the 1954 sowings showed t h a t three-year-old spruce and alpine f i r s e e d l i n g s were not affected by s tand condi t ion. Douglas f i r seedl ings were s i g n i f i c a n t l y t a l l e r on the logged area than on the burned area whereas lodgepole pine seedlings were s i g n i f i c a n t l y t a l l e r on the burned area than on the logged area.

Upland vegeta t ion s i te types had no e f f e c t on germination and early survival of spruce, alpine fir, Douglas f i r and lodgepole pine on scar i f ied seedbeds in the 1954 sowings, nor i n t h e 1953 sowings of spruce and a lp ine f i r . However, i n t h e 1955-56 sowings of spruce and Douglas f i r , t h e w e t t e r 0 s i t e gave s i g n i f i c a n t l y b e t t e r r e s u l t s t h a n t h e d r i e r A-D s i t e .

The first-growing-season survival trend, by s i t e , on humus seedbeds i n t h e n a t u r a l s t a n d f o r t h e 1953 and 1954 sowings has been mentioned under the heading of "Results". In 1953, the bes t su rv iva l of spruce and alpine f i r occurred on the 0 s i t e (the wet tes t o f the up land s i tes , with the g rea t e s t number of species and density of ground p l a n t s ) , followed by the A-D s i te ( in te rmedia te in mois ture condi t ions and dens i ty of ground p l a n t s ) , and t h e C-M s i t e ( t h e d r i e s t of t he up land s i t e s , w i th the smallest number of species and density of ground plants). In 1954 a similar t rend in f i r s t - season surv iva l occur red for spruce , a lp ine fir and Douglas f i r on the C-M and A-D s i t e s b u t n o t on the 0 s i t e . The 0 s i t e was probably too wet f o r good germinat ion and survival in the wet te r - than-average growing season of 1954 (the 1953 growing season was s l i g h t l y drier-than-average). Smith (1955), working with si tes similar t o the C-M and A-D s i t e s of this s tudy, a lso ment ions that s i t e s may be arranged i n order from wet t o dry with spruce becoming es tab l i shed in l a rger p ropor- t i o n s on the we t t e s t of n a t u r a l l i t t e r and moss seedbeds.

- 17 - The discussion above ind ica tes tha t up land vege ta t ion s i te types

had a r e l a t i v e l y minor influence on germination and early survival of seedlings as compared to s tand condi t ions . The preparation of 12- t o 18-inch seed spots, by removal or mixing of ground vegetation and humus with minera l so i l , and the addi t iona l d i s turbance of vegetation surrounding spots , cer ta inly modif ied the effect of vege ta t ion s i t e types. Smith (1955) a l s o comments t h a t where s c a r i f i c a t i o n o r burning a r e employed, most s i t e d i f f e r e n c e s t e n d t o b e masked and, i n t h e l o n g run, differences between si tes w i l l probably become evident in t e rms of growth and l a t e r s u r v i v a l .

The swampy Equisetum-Sphagnum s i t e t ype p roved t o be more of s i l v i c a l t h a n of s i l v i c u l t u r a l i n t e r e s t b e c a u s e of the generally excellent f irst-growing-season germination and survival on mound seedbeds of a l l species sown ( sp ruce , a lp ine f i r , Douglas f i r and pine ) followed by poor s u r v i v a l a f t e r t h e f i r s t season. Moisture, temperature and light condi- t i o n s were apparent ly idea l on mounds for good r e g e n e r a t i o n i n t h e f i r s t growing season.

I n t h e 1954 sowings, first-growing-season germination and surv iva l on burned area mound seedbeds were the highest of t h e e n t i r e 1954 experiment f o r a lpine f i r , Douglas f i r and pine and almost the highest for spruce (logged area mounds gave s l i g h t l y b e t t e r r e s u l t s t h a n b u r n e d a r e a mounds). I n t h e 1953 sowings of spruce and alpine f ir , mound seedbeds under a l l stand conditions gave the highest f i rs t -season germinat ion and surv iva l of the ent i re 1953 experiment.

In the wetter-than-average spring of 1954 excess water was the main fac tor in f luenc ing seeding success , e i ther as a d i r e c t e f f e c t by reduc- ing germination o r , i n d i r e c t l y by the softening-up and washing-down of mounds. In the s l igh t ly d r ie r - than-average spr ing of 1953 t h e e f f e c t of excess water was not as grea t as i n 1954.

Light and possibly temperature were also important factors inf luenc- ing the germination of p ine (Tackle, 1959) and t o a l e s se r ex t en t of Douglas f i r . The most rapid and highest germination occurred on t h e burned area ( the most open stand condition), followed by the logged area and the natural s tand.

The h igh mor ta l i ty a f te r the f irst growing season was due mainly t o a dense invasion of grasses and horsetai l and, in some cases , t o so f t en - ing up and breaking-down of mounds in per iods o f h igh water , par t icu lar ly in t he sp r ing . In fu tu re work w i t h t h i s s i t e t y p e , mounds should probably be made la rger than those o f th i s s tudy . As t h e r e s u l t s have shown, only a l p i n e f i r showed promise as a s p e c i e s f o r u s e i n r e f o r e s t a t i o n of t h i s s i t e t y p e . The swamp species of tamarack and black spruce should also be experimented wi th i n f u t u r e work.

- 18 -

Climate and Time of Seedinq f

Place (1955), i n a de ta i led s tudy on t h e s i l v i c s of spruce (white, red and black spruce) and f i r (balsam f i r ) in sou the rn New Brunswick, concluded t h a t t h e most s t r iking point brought out by the invest igat ion was the powerful inf luence which var ia t ions in the ra infal l dur ing the warm season exerted on regeneration. The c l i m a t e , e s p e c i a l l y r a i n i n June and July, governed the success of regeneration. Rain must be abundant and well distributed during May, June and Ju ly , espec ia l ly the l a t t e r two months, o r seedbeds must be na tura l ly mois t . Drought and heat together were the chief cause of seedl ing deaths .

It was v e r y d i f f i c u l t t o d i s e n t a n g l e t h e e f f e c t s of drought and heat , a l though the role of heat was mainly in drying the surface of seedbeds. Smith (1955), i n a deta i led s tudy on t h e s i l v i c s o f Engelmann spruce and alpine f i r i n t h e S o u t h e r n I n t e r i o r of B r i t i s h Columbia, con- c luded that , of the c l imat ic factors , moisture was t h e f a c t o r most limit- ing to germinat ion and f i rs t -year survival . Weetman (1958), i n d i scuss ing the genera l top ic o f d i rec t seeding , c lass i f ied c l imate (mois ture and temperature conditions during and immediately following the germination per iod) as one of t he t h ree main fac tors a f fec t ing t ree seedl ing es tab- l ishment.

A comparison of the results of the 1953 and 1954 sowings i n t h i s pro jec t and a study of t he c l ima te da t a fo r 1953 and 1954 a l s o poin ts out the importance to r egene ra t ion of r a i n f a l l i n t h e s p r i n g a n d e a r l y ( summer. I n 1953, about eight viable seeds were needed t o produce one establ ished spruce seedl ing on the logged and burned areas. In 1954 only four viable seeds were needed t o produce one establ ished seedl ing. Rain- f a l l a t Aleza Lake f o r May, June and July of 1953 was 1.48, 3.07 and 2.22 inches respect ively and f o r May, June and July of 1954, 2.26, 3.38 and 2.38 inches respect ively.

The 1955-56 sowings of spruce and Douglas f ir emphasized t h e s i g n i f - icance to regenerat ion of the dis t r ibut ion as we l l as the abundance of r a i n f a l l i n May, June and July. Rainfall f o r May, June and July of 1956 was 0.20, 4.25 and 1.24 inches respectively. Of the four sowing da tes (September 3 and November 2, 1955; June 2 and June 28, 1956) the June 2 sowing proved t o be the most successful for spruce on both the logged and burned areas because of the very dry May (0.20 inches; average : 3.34 inches) and drier-than-average July (1.24 inches; average : 2.43 inches ) .

The June 2 sowing was a l s o t h e most successfu l for Douglas f ir on the burned area, al though not on the logged area, where the f a l l sowings of September 3 and November 2 proved t o be b e s t . This may aga in ind ica te tha t l igh t and poss ib ly s l igh t ly h igher t empera tures a re necessary for the best germination of Douglas fir as compared t o sp ruce . Fa l l sowings on the more shaded and cooler logged area benef i ted by germina t ion in the warm May of 1956 (germination almost completed by June 6 ) .

c

- 19 - Another important factor which must be considered in regard to

time of seeding i s the use of poisons to protect seed against rodents . (The general problem of rodents w i l l be discussed in the following sec t ion . ) S ince r e su l t s of rodent tes ts of th i s s tudy ind ica ted a rodent problem, the use of poisons to protect seed against rodents appears necessary. Kverno and Hartwell (1957), i n a progress report on experimental seeding s tudies in the Pacif ic Northwest , s ta te that recent successful poisons (Endrin and Tetramine) do not remain f u l l y e f f e c t i v e i n t h e f i e l d for longer than a few months a f t e r s eed ing . This would limit seeding to the spr ing months, which i s a l s o d e s i r a b l e f o r spruce from a s i l v i c a l p o i n t of view, as discussed above.

For Douglas f i r on logged-over area, however, s t r a t i f i c a t i o n o f seed might benefit germination. The 14-day s t r a t i f i c a t i o n p e r i o d used f o r t h e 1956 spring sowings w a s probably too short for Douglas f i r . A 21-day s t r a t i f i c a t i o n of spruce, alpine f ir , Douglas f i r and pine seed i n t h e 1954 sowings appeared t o be of no benefi t to germinat ion, a l though, aga in , the s t ra t i f ica t ion per iod was probably too short, p a r t i c u l a r l y f o r a l p i n e f i r and p ine .

Time of seeding must a l s o be governed by spring temperatures warm enough to i n i t i a t e ge rmina t ion . S ince r e su l t s of rodent tes ts of t h i s study gave every indication of a rodent problem, there seems t o be no point in exposing seed to rodents ear ly in the spr ing, when temperatures a r e s t i l l too low for rapid germinat ion of seed. Temperatures of 68OF. t o 86OF. are suggested as su i tab le for germina t ion of t r u e f i r s and optimum for the spruces (U.S. Forest Service, 1948). Heit (1949) con- cluded tha t red and white spruce w i l l not germinate promptly or completely a t temperatures below 68OF. Mork (1934) concluded that low temperatures a r e t h e main l imi t ing f ac to r i n ge rmina t ion of Norway spruce (Picea abies ( L . ) Karst. ) i n no r the rn Norway. Fluctuating temperatures between 47O and 7 8 O ~ . favour germination of lodgepole pine (Bates, 1930). Jack pine (Pinus banksiana Lamb.) germination takes place when a i r temperature maxima reach 640F. (Rudolf, 1958). Place (1955) gives 60'~. t o 90°F. as favourable temperatures for good germination and survival of spruces and t r u e f i r s .

The average date when a i r temperature maxima reach 60 F . a t Aleza Lake i s May 6 (range: May 1 t o May 1 4 ) . The e a r l i e s t d a t e of seeding i n f u t u r e work should, therefore, be about May 1. I n t h e 1953 sowings (a s l ight ly dr ier- than-average spr ing and e a r l y summer), the germination per iod for spruce las ted about 45 days. In the 1954 sowings (a wet ter- than-average spring and early summer), germination continued for 60 days a f te r seeding for spruce and Douglas f i r and f o r 90 days a f t e r s eed ing f o r a l p i n e f i r and pine. Place (1955) concludes, however, that spruce and f ir seedlings germinating after the middle of July seldom live through the win ter in the open or under a canopy. The l a t e s t d a t e of seeding should be, therefore, about June 1, t o a l low for a t l e a s t a 45-day germination per iod. Resul ts of the 1955-56 sowings a l s o i n d i c a t e t h a t t h e l a t e s t d a t e of seeding should be about June 1, since June 28 sowings were poorer than June 2 sowings f o r both spruce and Douglas f i r .

0

- 20 - r

Rodents

Westman (1958), i n reviewing the problems of direct seeding, c lass i f ied rodents as one of the three main f a c t o r s a f f e c t i n g t r e e seedling establishment. Studies of direct seeding of Douglas f ir i n the southern coas ta l reg ion of Br i t i sh Columbia (Garman and Orr-Ewing, 1949; Orr-Ewing, 1950; Finnis, 1955; B r i t i s h Columbia Forest Service, Forest Research Reviews, 1956 t o 1960) have shown tha t rodents a re t h e main obstacle to success in seeding. Smith (1955), working with Engelmann spruce and alpine fir i n t h e Southern Inter ior of Bri t ish . Columbia, concluded that, other than drought, rodents were the most important cause of seed and seedl ing losses .

Results of the 1954 sowings of th is study showed h igh ly s ign i f i can t d i f fe rences in th i rd-year surv iva l between screened and unscreened seed spo t s fo r a l l species sown (spruce , a lp ine f i r , Douglas f ir and p i n e ) ; and unscreened seed spots of the 1955-56 sowings were complete failures by the end of t h e f i r s t growing season for the two species sown (spruce and Douglas f i r ) . Therefore, in any future direct seeding work i n t h e Cen t ra l In t e r io r of B r i t i s h Columbia, a rodent problem must be ant ic ipated.

Other Factors AffectinLSeedling - Establishment

Observations were made of seedling losses due t o smothering and crushing by l i t t e r and frost heaving. However, t h e c o l l e c t i o n of data was not designed to de te rn ine these losses accura te ly . Minor losses were caused by large animals, mainly by moose trampling on seedbeds. A few seedbeds were a l s o l o s t because of the cur iosi ty of bears for the screens which covered seed spots i n t h e f i rs t growing season.

,,.. . - _ , . , . . , SUMMARY AND CONCLUSIONS

During the growing seasons of 1953 t o 1957 a study was made of some of the factors affecting germination and early survival and growth of white spruce, alpine f i r , Douglas f i r and lodgepole pine at Aleza Lake i n t h e C e n t r a l I n t e r i o r of Br i t i sh Columbia. Factors invest igated were : (1) seedbed; (2 ) stand condition; ( 3 ) vegeta t ion s i te type ; (4) c l imate ; ( 5 ) time of seeding; and (6) rodents .

The following conclusions may be used t o guide future direct seed- ing work in t he gene ra l a r ea no r th and east of Prince George and west of the Rocky Mountains ( t h e r e l a t i v e l y wet Rocky Mountain Trench) :

(1) The preparation of mineral soil seedbeds i s e s s e n t i a l t o _good -establishment of white- spurce, alpine f i r , Douglas fir and lodge- pole pine under a l l s tand condi t ions tes ted (natural s tand and 10- year-old logged and burned areas). Fair t o good first-growing-season survival of spruce, alpine f i r and Douglas f i r a l s o o c c u r r e d on humus seedbeds in t he na tu ra l s t and , bu t th i s was followed by high mortali ty of s e e d l i n g s a f t e r t h e f i r s t s e a s o n . Whether these f i r s t - season seed- l ings could be saved by removal of the s tand in the win ter fo l lowing seedling establishment i s no t ce r t a in .

- 21 - ,(2) O f the two types of scar i f ied seedbeds involved in th i s

study, generally speaking, the mineral seedbed proved t o b e t h e b e s t seedbed i n r e g a r d t o s u r v i v a l of seedlings, whereas the mixed seedbed proved t o be b e s t i n r e g a r d t o h e i g h t growth of seedl ings.

-.

( 3 ) I f seedbed preparation i s t o be car r ied ou t by hand, seed spots should be made at l e a s t 12 by 12 i n c h e s i n s i z e , i n o r d e r t o p r o -

‘duce adequate disturbed seedbed for good germination and reduce competi- t i o n b y ground vegetatfon.

(4) The logged area (about 10 years o ld) p resented- the bes t conditions for good germination and early survival of spruce and alpine fir, whereas the burned area (about 10 years o ld) p resented the bes t condi t ions for good germination and early survival of Douglas f i r and lodgepole pine.

( 5 ) Upland vegeta t ion s i te types , as modified by the preparat ion of 12-to 18-inch seed spots, had a r e l a t i v e l y minor influence on germina- t i o n and ea r ly su rv iva l of seedlings as compared to s t and cond i t ions .

(6 ) O f the species sown (white spruce , a lp ine f i r , Douglas f i r and lodgepole pine ) only alpine f ir showed promise as a species for use i n re fores ta t ion on mounds of the swampy Equisetum-Sphagnum s i t e t y p e .

( 7 ) R a i n f a l l i n t h e s p r i n g and e a r l y summer (May, June and July) of t h e f irst growing season had a strong influence on success of regen- e r a t i o n . I n 1953 (a s l ight ly dr ier- than-average spr ing and e a r l y summer) about eight viable seeds (protected against rodents) were needed t o produce one established spruce seedling (four o r f ive years o l d ) on scar i f ied seedbeds in the logged and burned a reas . In 1954 (a wetter-than-average spring and early summer) only four viable seeds were needed t o produce one establ ished seedl ing ( three o r four years o ld) . Therefore , in fu ture seedl ings of spruce about ten viable seeds (protected against rodents) should be sown per seedspot t o g i v e satis- f a c t o r y r e s u l t s in both d ry as w e l l as w e t years. This number could a l s o be used as a guide i n s e e d i n g a l p i n e f i r , Douglas fir and lodgepole pine. Ten viable seeds should be a maximum as w e l l as a minimum number of s e e d s , i n o r d e r t o limit t h e p o s s i b i l i t y of obtaining too many seed- l i n g s , as shown i n P l a t e s 1 t o 3 of t h i s paper, i n which 50 viable seeds per seedspot were sown.

(8) A s influenced by average moisture and temperature conditions i n t h e s p r i n g and e a r l y summer, and the need for t reat ing seeds with poisons to protect against rodents , the best t ime for seeding spruce and Douglas-fir i s about May 1 t o J u n e ~ 1. For Douglas f i r on logged- ove r a r eas , s t r a t i f i ca t ion of seed may be necessary.

(9) Protection of seed against losses t o rodents by t r ea t ing w i th recent successful poisons (endrin o r te t ramine) appears essent ia l .

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ALEXANDER, R . R ., 1958. S i l v i c a l c h a r a c t e r i s t i c s of subalpine f i r . u.s . Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Exp Sta . , For t Collins, Colorado. Station Paper No. 32.

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4 CANDY, R . H . , 1951. Reproduction on cut-over and burned-over land i n Canada. Canada, Dept. Resources and Development, Forestry Branch, For. Res. Div., Silv. Res. Note No. 92, 224 pp.

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HANDLEY, W R . C J 1954. Mull and mor fo rma t ion i n r e l a t ion t o f o r e s t Soils. Imperial Forestry Inst i tute , Oxford, and Br i t i sh Fo res t ry Commission, Bul. No. 23.

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KVERNO, N . B., and HARTWELL, H. D . , 1957. Progress report Pacif ic Northwest 1955-1956 and 1956-1957 experimental seeding studies. Unpublished report, U. S. Dept. of I n t e r i o r , F i s h and Wildlife Service, Wildlife Research Laboratory, Denvor, Colorado.

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- 24 - MORK, E., 1934. Temperature as a f a c t o r of regeneration i n spruce

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