J u l y 1979

PNW-334

VEGETATIVE PROPAGATION OF 11 COMMON

EDITOR'S

ALASKA WOODY PLANTS

FILE COPY

Patricia ~ o l l o w ,l/ a ~ Research A s s i s t a n t Department o f H o r t i c u l t u r a l S c i e n c e and Landscape A r c h i t e c t u r e U n i v e r s i t y of Minnesota S t . P a u l , Minnesota and

John Zasada, s i l v i c u l t u r i s t I n s t i t u t e o f Northern F o r e s t r y P a c i f i c Northwest F o r e s t and Range Experiment S t a t i o n U. S. Department o f A g r i c u l t u r e , F o r e s t S e r v i c e F a i r b a n k s , Alaska

ABSTRACT V e g e t a t i v e p r o p a g a t i o n t r i a l s were conducted with stem, r o o t , and rhizome c u t t i n g s of Alnus, A r c t o s t a p h y l o s , Ledum, Populus, S a l i x , Shepherdia, Vaccinium, and Viburnum. With t h e e x c e p t i o n o f Alnus i n c a n a and Shepherdia c a n a d e n s i s , stem c u t t i n g s o f a l l s p e c i e s produced some r o o f s . Softwood stem c u t t i n g s o f S a l i x bebbiana and Viburnum e d u l e r o o t e d much b e t t e r than hardwood c u t t i n g s o f the-same s p e c i e s ; hardwood and softwood stem c u t t i n g s of o t h e r s p e c i e s were about equal i n performance. Rooting media, wounding, and hormone t r e a t m e n t s d i d n o t a f f e c t r o o t i n g o f stem c u t t i n g s i n t h e m a j o r i t y o f c a s e s . Root o r rhizome c u t t i n g s of vaccinium uliginosum and Shepherdia c a n a d e n s i s appeared more promising f o r v e g e t a t i v e p r o p a g a t i o n o f t h e s e s p e c i e s t h a n stem c u t t i n g s . KEYWORDS:

V e g e t a t i v e p r o p a g a t i o n , stem c u t t i n g s , r o o t c u t t i n g s , rhizome c u t t i n g s , woody p l a n t s , A l a s k a .

L ' ~ tt h e time o f t h i s s t u d y , P a t r i c i a Holloway was Research A s s i s t a n t , A g r i c u l t u r a l Experiment S t a t i o n , U n i v e r s i t y o f Alaska, Fairbanks.

INTRODUCTION

Restoration and/or rehabilitation of sites severely disturbed by pipeline, highway or similar construction, and mining is often mandated by law. Although the 'most common practices used to replace vegetation are best described as agronomic (grass seeding and fertilization), there is increasing interest in the use of native plants (Johnson and Van Cleve 1976, Freeman et al. 1977). Since woody plants are a major . component of forested and nonforested Alaska ecosystems, there is a need to determine methods for obtaining adequate quantities of suitable plant materials for revegetation purposes. Woody plant materials can be propagated by seed or by various vegetative methods. There is a great deal of information available on ways to propagate woody plants (Hartmann and Kester 1975, U.S. Department of Agriculture, Forest Service, 1974);however, its general applicability to Alaska species is not known. For example, it was generally believed that North America willow seed was nondormant and could not be stored. Research with Alaska willows identified species with dormant seed and revealed that seed of at least five species (dormant and nondormant seeded species) could be stored for up to 3 yrs without a significant reduction in viabilityL/ (Brinkman 1974, Zasada and Viereck 1975, Zasada and Densmore 1977). Results of this type suggest that surveys of . reproductive characteristics may be necessary to determine the full potential of each species for revegetation programs. This report summarizes the results of a study designed to examine the rooting response of stem cuttings of 11 native Alaska shrub and tree species in a controlled environment: Scientific name 31

Common name

AZnus crispa (Ait.) Pursh ssp. crispa AZnus incana ( L . ) Moench ssp. t e n u i f o z i a (Nutt .) Breitung Arctos taphy Zos uva-ursi (L .) Spreng . var . uva-ursi Ledwn palustre L . subsp. groenlandicwn (Oeder) Hult . PopuZus batsamifera L. . SaZix alaxensis var . longisty l i s (Rydb.) Schneid. SaZix bebbiana Sarg . SaZix scouZeriana Barratt. Shepherdia canadensis (L .) Nutt . Vacciniwn uZiginoswn L . ssp. atpinurn (Bigel .) Hult . vibwrzwn eduZe (Michx .) Raf .

American green alder Thinleaf alder Bearberry Labrador tea Balsam poplar Feltleaf willow Bebb willow Scouler willow Buffaloberry Bog blueberry Highbush cranberry

Unpublished data on file at Institute of Northern Forestry, USDA Forest Service, Fairbanks, Alaska.

31 Nomenclature

follows ~ultgn (1968)

Smaller s t u d i e s were a l s o undertaken t o t e s t t h e s e s p e c i e s i n t h e f i e l d and t o examine shoot production p o t e n t i a l of underground p a r t s of these species.

METHODS Hardwood and Softwood Stem Cuttings Hardwood stem c u t t i n g s were c o l l e c t e d between September 17 and October 15, 1976, from s i t e s near Fairbanks, Alaska. A l l material was moistened, wrapped i n polyethylene bags, and placed i n cold s t o r a g e a t 4.s0C f o r approximately 2 wk a f t e r which it was trimmed f o r f u r t h e r treatment. Cuttings of SaZix spp., AZnus spp., and PopuZus balsamifera consisted e n t i r e l y o f new growth with t h e proximal c u t not g r e a t e r than 1 cm below a node, and with a minimum of t h r e e v i a b l e buds. The c u t t i n g s o f t h e remaining shrub species c o n s i s t e d o f a l l a v a i l a b l e new growth p l u s a heel o f 1-yr-old t i s s u e . The stems o f each SaZix s p e c i e s were f u r t h e r separated i n t o base and t i p c u t t i n g s . The base c u t t i n g contained t h e o l d e s t o f t h e newly hardened t i s s u e immediately above t h e 1-yr-old stem t i s s u e . The t i p c u t t i n g s contained stem t i s s u e from t h e apex of t h e newest growth. The c u t t i n g s were divided i n t o two groups. One group was buried i n f l a t s of s t e r i l i z e d n a t i v e p e a t which were wrapped i n opaque polyethylene bags and placed i n cold s t o r a g e f o r l a t e r p l a n t i n g i n t h e f i e l d . The remaining group of c u t t i n g s was p l a n t e d immediately and placed on an i n t e r m i t t e n t mist propagation bench i n t h e greenhouse (220C average a i r temperature, 26.7OC bottom h e a t ) . The mist c y c l e was approximately 5 s e c of mist every 15 min. The propagation bench was divided i n t o 5 randomized blocks with 20 treatments p e r block and 82 c u t t i n g s p e r treatment. Supplemental l i g h t i n g was provided by two 40-watt cool-white f l u o r e s c e n t bulbs suspended 1 m above t h e bench. Cuttings o f each s p e c i e s were divided between two propagation media, h o r t i c u l t u r a l grade p e r l i t e and sand. Further treatments within these media included: 1. Control. 2. Powdered auxin treatment. The proximal portion of each stem c u t t i n g was dipped i n t o a powdered formulation o f Indole-3-butyric a c i d ( I B A ) , Hormodin # 3 . 3 . Wounding treatment. The bark o f t h e proximal end of each c u t t i n g was severed with t h e pointed t i p o f a k n i f e f o r approximately 2-3 cm upward from t h e base. 4. Powdered auxin-wounding treatment. A combination o f treatments 2 and 3 above. 5. Liquid auxin-wounding treatment. Following wounding a s i n treatment 3 above, c u t t i n g s were soaked f o r 5 min i n a concentrated, 2,000 ppm l i q u i d formulation o f IBA.

Cuttings o f a l l treatments were checked t h r e e times wekly f o r successf u l rooting, which was defined a s t h e first i n d i c a t i o n of root emergence

from t h e c u t t i n g - surfaces. The data recorded f o r each treatment included t h e percentage of successfully rooted c u t t i n g s f o r each species and t h e average time it took f o r r o o t s t o emerge. The rooted c u t t i n g s were planted i n f l a t s of moist peat f o r p o s s i b l e t r a n s p l a n t i n g i n t o t h e f i e l d sites. Rooting percentages were t r e a t e d s t a t i s t i c a l l y with t h e analysis o f variance f o r randomized complete block design and, where applicable, with Duncan's New Multiple Range Test a t t h e 5-percent l e v e l (Steel and T o r r i e 1960). With s l i g h t v a r i a t i o n s , t h i s experimental design was repeated f o r t h e study of softwood c u t t i n g s . Cuttings were c o l l e c t e d from s i t e s near Fairbanks, Alaska, between J u l y 5 and J u l y 19, 1977, and immediately trimmed t o c u t t i n g length f o r f u r t h e r treatment: Species

Average length (cm)

Alnus erispa AZnus incana Arctostaphy Zos uva-ursi Ledwn palustre Popu Zus ba Zsamifera SaZix aZmensis SaZix bebbiana SaZix scouZeriana Shepherdda eanadensis Vacciniwn uZiginoswn V i b m m eduZe Leaves were removed from t h e lower 2-4 cm of each c u t t i n g . A l l o t h e r leaves were trimmed t o approximately three-quarters o f t h e i r o r i g i n a l s i z e t o reduce water l o s s . The softwood c u t t i n g s were planted i n t h e greenhouse i n sand o r p e r l i t e media a f t e r undergoing i d e n t i c a l t r e a t ments a s t h e hardwood c u t t i n g s . The propagation bench design was i d e n t i c a l except f o r t h e elimination of supplemental l i g h t i n g and a s l i g h t l y s h o r t e r m i s t cycle averaging 5 sec every 12 min.

Root and Rhizome Cuttings

,

Root and rhizome c u t t i n g s were c o l l e c t e d from SaZix spp., AZnus spp., Skepherdia canadensis, Arctostaphy 20s uva-ursi , viburnum edule , Vacciniwn ~Ziginoswn,Ledm palustre, and PopuZus baZsamifera from s i t e s near Fairbanks, Alaska, between September 17 and October 15, 1976. Sections 5 t o 10 cm long were buried h o r i z o n t a l l y i n wooden f l a t s containing s t e r i l i z e d n a t i v e peat: 25 c u t t i n g s p e r f l a t and 2 f l a t s p e r species. One f l a t of each species was moistened and placed immediately i n t h e greenhouse. The f l a t s were enclosed i n individual, c l e a r polyethylene bags t o increase moisture r e t e n t i o n . Data recorded included t h e percentage of c u t t i n g s producing shoots, t h e number of days t o maximum shoot emergence, percent s u r v i v a l , and new root production following a 2-mo growing period. The remaining group of f l a t s was enclosed i n individual, opaque polyethylene bags and placed i n cold storage f o r 6 mo. Following t h i s period, 15 of t h e 25 c u t t i n g s o f each species were planted i n f l a t s of

p e a t i n t h e greenhouse and handled i d e n t i c a l l y t o t h e f i r s t group o f f l a t s . The remaining 10 c u t t i n g s of each s p e c i e s were returned t o c o l d s t o r a g e f o r t h e d u r a t i o n of w i n t e r , a f t e r which they were planted i n the f i e l d . Data species planted planted

were recorded f o r t h r e e planted d i r e c t l y i n t h e i n t h e greenhouse a f t e r i n the f i e l d s i t e a f t e r

groups o f c u t t i n g s : c u t t i n g s o f each greenhouse a f t e r c o l l e c t i o n , c u t t i n g s a 6-mo cold s t o r a g e period, and c u t t i n g s an approximate 9 4 0 cold s t o r a g e p e r i o d .

Field Study One o f t h e two f i e l d s i t e s was l o c a t e d a t t h e A g r i c u l t u r a l Experiment S t a t i o n farm a t t h e U n i v e r s i t y o f Alaska, Fairbanks. The s o i l a t t h i s s i t e i s c l a s s i f i e d a s lanana s i l t loam (Rieger e t a l . 1963). The land had been c l e a r e d more than 10 y r ago. C u l t i v a t i o n i n t h e study a r e a during t h e p a s t 5 y r was l i m i t e d t o mechanical weed c o n t r o l . The f i e l d s i t e was n e a r l y l e v e l , and s o i l moisture content a t t h e time of p l a n t i n g was 19 p e r c e n t . C u t t i n g s p l a n t e d a t t h i s s i t e included h a l f of t h e hardwood stem c u t t i n g s which had been maintained i n f l a t s o f p e a t i n c o l d s t o r a g e during t h e w i n t e r and t h e rooted c u t t i n g t r a n s p l a n t s from t h e greenhouse hardwood c u t t i n g study. The unrooted hardwood stem c u t t i n g s were p l a n t e d on June 6, 1977, and subsequent c a r e of experimental p l o t s c o n s i s t e d of hand weeding. Cuttings were d i r e c t l y i n s e r t e d i n t o t h e s o i l t o three-quarters t h e i r l e n g t h a f t e r being t r e a t e d a s follows:

1. Control. 2. Liquid auxin t r e a t m e n t . The proximal end o f t h e c u t t i n g s was soaked f o r 5 min i n a 2,000 ppm l i q u i d formulation of I B A . 3 . Powdered auxin t r e a t m e n t . The proximal p o r t i o n of each c u t t i n g was dipped i n t o a powdered formulation (Hormodin #3) o f IBA. 4 . R e p e t i t i o n of t r e a t m e n t s 1, 2 , and 3 with t h e a d d i t i o n of soaki n g t h e d i s t a l p o r t i o n o f t h e stem c u t t i n g s i n a commercially prepared antitranspirant. A randomized complete block design was used with f o u r - b l o c k s of 6 t r e a t m e n t s and 65 c u t t i n g s . p e r t r e a t m e n t . Successful r o o t i n g and establishment w i t h i n each treatment were recorded a s t h e percentage of c u t t i n g s t h a t survived & f t e r 3 mo. C u t t i n g s which survived produced leaves and new buds. R e s u l t s were t r e a t e d s t a t i s t i c a l l y with an a n a l y s i s of v a r i a n c e f o r randomized complete block design and where a p p l i c a b l e , with Duncan's New Multiple Range Test a t t h e 5-percent l e v e l of s i g n i f i c a n c e ( S t e e l and T o r r i e 1960).

The rooted c u t t i n g t r a n s p l a n t s were removed from t h e greenhouse on June 10, 1977, and hardened i n a coldframe f o r 2 wk p r i o r t o p l a n t i n g . C u t t i n g s were p l a n t e d with a b a l l of s a t u r a t e d p e a t surrounding t h e r o o t s . No t r e a t m e n t s were administered a f t e r p l a n t i n g . Results were recorded a s t h e p e r c e n t s u r v i v a l following a 3-mo growing season. The second f i e l d s i t e was l o c a t e d i n t h e Bonanza Creek Experimental Forest approximately 21 miles south o f Fairbanks, Alaska. The s o i l a t t h i s s i t e i s c l a s s i f i e d a s S t e e s e s i l t loam (Furbush and Schoephorster

1977). The experimental s i t e was located on an east-facing, 49-percent roadside slope with s o i l moisture content o f 12 percent a t t h e time o f p l a n t i n g . Limited n a t u r a l regeneration of white spruce, b i r c h , and willow was evident, but cover from t h e s e p l a n t s was minimal. The s i t e was not prepared p r i o r t o p l a n t i n g nor were any treatments administered during t h e growing season. Cuttings planted a t Bonanza Creek included t h e remaining unrooted hardwood stem c u t t i n g s and t h e cold s t o r a g e t r e a t e d root, rhizome, a n d . sucker c u t t i n g s . Both were planted on June 13, 1977. Treatments, experimental design, d a t a c o l l e c t i o n , and a n a l y s i s f o r t h e unrooted hardwood c u t t i n g s were i d e n t i c a l t o those f o r Experiment S t a t i o n farm s i t e . The root c u t t i n g s were planted h o r i z o n t a l l y , approximately 2 cm below t h e s o i l surface, and t h e percent shoot production was recorded f o r each s p e c i e s .

RESULTS Rooting in a Controlled Environment

Alnus spp. Only 3 o f a t o t a l o f 1,000 A . crispa hardwood c u t t i n g s formed r o o t s . A l l softwood c u t t i n g s f a i l e d t o produce r o o t s . Neither hardwood nor softwood c u t t i n g s o f A. incana produced r o o t s . Arctostaphylos uva-msi. i n i t i a t e d roots (table 1 ) . s i g n i f i c a n t f o r e i t h e r type r o o t s formed randomly along approximately 6 wk o f bench

Both hardwood and softwood stem c u t t i n g s Treatment and media d i f f e r e n c e s were not of c u t t i n g . Thin, f i b r o u s c l u s t e r s o f t h e buried p o r t i o n o f t h e stems within planting.

Ledwn palustre. Few r o o t s were i n i t i a t e d on e i t h e r hardwood o r The number of c u t t i n g s rooting softwood stem c u t t i n g s ( t a b l e 1) s u c c e s s f u l l y was not s u f f i c i e n t t o show any r e a l d i f f e r e n c e s between treatments. Diffuse c l u s t e r s of very t h i n , branching r o o t s formed along t h e buried stems, mostly within t h e h e e l o r 1-yr-old t i s s u e . Rooting generally occurred within 3 mo o f p l a n t i n g .

.

Populus balsamifera. Both hardwood and softwood stem c u t t i n g s had r e l a t i v e l y high rooting percentages ( t a b l e 1 ) . Root i n i t i a t i o n gene r a l l y occurred within 3 wk a f t e r p l a n t i n g i n t h e greenhouse. I n i t i a l root ,formation occurred near a v i a b l e bud; however, f u r t h e r r o o t i n g occurred randomly along t h e buried stem. Some c a l l u s t i s s u e was formed on t h e base of t h e c u t t i n g s which were t r e a t e d with t h e powdered f o r mulation of I B A . Roots were preceded by t h e formation of p r o t r u s i o n s of c e l l s which subsequently s p l i t t h e bark and through which t h e r o o t s emerged. The formation of t h e s e p r o t r u s i o n s occurred very quickly a f t e r bench p l a n t ing, even on t h e c u t t i n g s which eventually f a i l e d t o produce r o o t s . Treatment d i f f e r e n c e s were s i g n i f i c a n t f o r both softwood and hardwood stem c u t t i n g s . Wounding seemed t o enhance r o o t production i n hardwood c u t t i n g s , but r o o t s d i d not emerge s o l e l y from t h e severed region. Wounds which were subsequently t r e a t e d with powdered I B A tended t o form c a l l u s t i s s u e i n t h e severed region r a t h e r than r o o t s .

Table 1--Rooting percentages o f hardwood and softwood stem c u t t i n g s o f s e l e c t e d Alaska woody p l a n t s Treatment Average performance Species

Type of cuttingy

Per1 it e

Sand Control

woundliquid 8

wound-

$:Fla*ed

Pow-

d;y:!

tird

only

Control

Wound 1i q u i d IBA

Pow-

$Kid :yJd IBA

$rd

Sand

only

Perlite

Hard-

Soft-

wood c2tting

wood cutting

g60abc 46a 50ab 69bc 53b .53b 63b 49b 60 56 62 64 54 48 42 56 62 54 62 50 44 40 44 32 62 50 58 56 60 56 78 66 60 58 64 60 55 45 58 50 Less t h a n 1 p e r c e n t r o o t e d Less t h a n 1 p e r c e n t r o o t e d 54 62 46 46 44 46 40 30

3 3 17 0 3 1 o f 250 c u t t i n g produced r o o t s 48ab 32a 92c 32a 80c 3 of 1,000 c u t t i n g s produced r o o t s 3 o f 1,000 > c u t t i n g s produced r o o t s No c u t t i n o s oroduced r o o t s No c u t t i n g s broduced r o o t s No c u t t i n g s produced r o o t s No c u t t i n g s produced r o o t s

' I

H = hardwood c u t t i n g

S = softwood c u t t i n g Hb = hardwood c u t t i n g H t = hardwood c u t t i n g Sb = softwood c u t t i n g S t = softwood c u t t i n g

from from from from

base o f annual growth t i p ( a p i c a l s e c t i o n ) o f annual growth base o f annual growth t i p ( a p i c a l s e c t i o n ) o f annual growth.

2/ I B A = I n d o l e - 3 - b u t y r i c a c i d . Treatments w i t h same l e t t e r i n a row were n o t s i g n i f i c a n t l y d i f f e r e n t a t PSO.05.

The absence o f l e t t e r s i n d i c a t e no s i g n i f i c a n t d i f f e r e n c e .

SaZix spp. S. alazensis stem c u t t i n g s produced numerous r o o t s from both hardwood and softwood c u t t i n g s with most r o o t formation occurring within 2 wk o f p l a n t i n g ( t a b l e 1 ) . Treatment d i f f e r e n c e s were not s t a t i s t i c a l l y s i g n i f i c a n t within e i t h e r t i p o r base c u t t i n g s o r between t h e sand and p e r l i t e media. S. ataxensis exhibited t h e d i f f u s e p a t t e r n of r o o t i n g (Chmelar 19T4), with r o o t s a r i s i n g near v i a b l e buds showing t h e b e s t growth. Results were s i m i l a r f o r S. scouleriana c u t t i n g s which rooted within 4 wk o f p l a n t i n g ( t a b l e 1 ) . Treatment d i f f e r e n c e s were not s t a t i s t i c a l l y s i g n i f i c a n t f o r e i t h e r base o r t i p c u t t i n g s nor between propagation media. Unlike S. aZaxensis c u t t i n g s , i n i t i a l r o o t i n g occurred a t t h e base (basal p a t t e r n (Chmelar 1974)) n e a r t h e proximal cut of t h e stem. Rooting progressed s p o r a d i c a l l y upward from t h e base along the buried stem s u r f a c e s . Few hardwood stem c u t t i n g s o f S. bebbiana rooted; r o o t i n g percentages were s i g n i f i c a n t l y higher f o r t h e softwood c u t t i n g s ( t a b l e 1 ) . The g r e a t d i f f e r e n c e between hardwood and softwood c u t t i n g s may not be c h a r a c t e r i s t i c of t h e s p e c i e s but p o s s i b l y a favorable response t o heavy pruning. The stem c u t t i n g s c o l l e c t e d i n t h e f a l l were noticeably very t h i n and s h o r t . The f a l l pruning o f growing t i p s appeared t o s t i m u l a t e p r o l i f i c shoot growth which was both t h i c k e r and longer than on t h e hardwood c u t t i n g s . These provided t h e bulk of t h e softwood c u t t i n g s f o r t h e summer experiments. Treatment d i f f e r e n c e s were n e g l i g i b l e f o r S. bebbiana softwood stem c u t t i n g s o f both t i p and base types. Rooting was random (Chmelar 1974) and was most p r o l i f i c on the p a r t of t h e stem s e c t i o n located immediately below the surface of t h e propagation medium.

Shepherdia canadensis. This s p e c i e s f a i l e d t o produce r o o t s from stem c u t t i n g s under t h e prescribed experimental greenhouse conditions. Both hardwood and softwood stem c u t t i n g s became s o f t and black s h o r t l y a f t e r p l a n t i n g . No evidence o f c a l l u s formation a t t h e proximal cut o r along wound surfaces was apparent. Vacciniwn uziginoswn. Rooting percentages from both hardwood and softwood stem c u t t i n g s o f blueberry were poor, and the number of rooted c u t t i n g s was n o t s u f f i c i e n t t o r e v e a l any s i g n i f i c a n t differences between treatments ( t a b l e 1 ) . Rooting generally occurred within two mo a f t e r p l a n t i n g , with t h i n , f i b r o u s r o o t s forming i n d i s c r i m i n a t e l y along t h e buried p o r t i o n o f t h e stem. V i b m m edule. From a t o t a l o f 300 highbush cranberry hardwood c u t t i n g s , 1 produced r o o t s . I n c o n t r a s t , softwood c u t t i n g s i n i t i a t e d numerous r o o t s ( t a b l e 1 ) . Cuttings rooted equally well i n t h e sand and p e r l i t e media, but rooting was more p r o l i f i c and averaged 2 wk e a r l i e r i n sand. Rooting was s i g n i f i c a n t l y increased by t r e a t i n g c u t t i n g s with powdered IBA. Roots generally formed within 6 wk a f t e r p l a n t i n g . They were i n l a r g e c l u s t e r s near t h e base o f each c u t t i n g , p r i m a r i l y i n t h e heel (1-year-old t i s s u e ) . Root emergence was preceded by t h e development of c e l l p r o t r u s i o n s along t h e buried p o r t i o n o f t h e stem a s much a s 1 wk before root emergence. Callus formation was minimal a t t h e base of t h e s e c u t t i n g s . Softwood c u t t i n g s whose leaves had f a l l e n o r had been removed d i d not produce r o o t s .

.

Root and Rhizome Changes

AZnus c r i s p a , Arctostaphy Zos uva-ursi , Ledwn palustre, PopuZus baZsam$fera, Shepherdia c a m d e n s i s , Vaeeinium u l i g i n o s m , and V i b m m eduZe were s u c c e s s f u l l y propagated from r o o t o r rhizome c u t t i n g s when p l a n t e d i n t h e greenhouse immediately a f t e r f a l l c o l l e c t i o n . Following c o l d treatment; only L. palustre, PopuZus balsamifera, Vacciniwn uZiginoswn,and V i b m m edule survived t o r e g e n e r a t e from t h i s type of material ( t a b l e 2 ) .

Table 2--Results o f propagation w i t h r o o t , rhizome, o r sucker c u t t i n g s Imnediately p l a n t e d Species

Atnus crispa ArctostaphtiZos - uva-ursi Ledm paZustre ~ouulus balsamifera Shephedia canadensis Vacciniwn utiginoswn Vibumwn edule

Cold' t r e a t e d Average no. days t o maximum emergence

Percent survival and r o o t production

percent success, shoot production

percent survival and r o o t production

4 60

100 100

0 0

0 0

7 46

64 100

31

100

0

73

53 100

49 14

root

24

100

0

0

46

rhizome

52

100

53

100

56

rhizome

100

28

100

100

28

Type of cutting

Percent success, shoot production

root root rhizome root

Field Trials Unrooted hardwood c u t t i n g s of PopuZus bazsamifera e x h i b i t e d varying degrees of r o o t i n g a t t h e two f i e l d s i t e s * ( t a b l e 3 ) . A t t h e Agricult u r a l Experiment S t a t i o n f i e l d s i t e , r o o t i n g was observed f o r a l l t r e a t ments within each block, but treatment d i f f e r e n c e s were not s t a t i s t i c a l l y s i g n i f i c a n t . Shoot growth a t t h e termination of t h e experimental growing

Table 3-- Average r o o t i n g and s u r v i v a l percentages o f hardwood stem c u t t i n g s o f PopzrZus baZsamifera L ssp. baZsamifera which were d i r e c t l y i n s e r t e d i n t o t h e ground a t f i e l d s i t e s

.

Treatment

Bonanza Creek Experimental F o r e s t

Control Powdered I B ~ ! L i q u i d IBA A n t i t r a n s p i r a n t (AT) Powdered IBA- (AT) L i q u i d IBA-(AT) Average performance, a l l treatments

"

IBA = I n d o l e - 3 - b u t y r i c acid.

8

Agricultural Experiment S t a t i o n

averaged 7 cm i n length f o r a l l treatments. Rooting and survival of c u t t i n g s a t t h e Bonanza Creek f i e l d s i t e appeared t o be confined t o t h e t r e a t e d c u t t i n g s and predominately t o the l i q u i d IBA treatment. The number of c u t t i n g s rooting s u c c e s s f u l l y was not s u f f i c i e n t t o show any d i f f e r e n c e s between t r e a t m e n t s . New shoot lengths averaged 5 cm, and considerable i n s e c t damage was noted on t h e new growth on several of t h e c u t t i n g s . With t h e exception of S. aZaxensis, none of t h e species survived one growing season i n t h e f i e l d .

,

More than 50 percent o f t h e rooted hardwood c u t t i n g s o f S a Z k aZaxensis , S. scouZeriana, and PopuZus baZsamifera survived t r a n s p l a n t i n g i n t o f l a t s o f peat from t h e greenhouse propagation bench. Subsequently f i f t y c u t t i n g s of each s p e c i e s were planted a t t h e A g r i c u l t u r a l Experiment S t a t i o n f i e l d s i t e . A t t h e conclusion of t h e growing season 38 percent of t h e S. scouZeriana, 44 percent o f t h e S. aZaxensis, and 8 2 percent of PopuZus baZsamifera t r a n s p l a n t s remained a l i v e . None o f t h e r o o t o r rhizome c u t t i n g s planted a t Bonanza Creek produced new shoots during t h e growing season.

DISCUSSION AND CONCLUSION The r e s u l t s reported here f o r hardwood and softwood c u t t i n g s i n d i c a t e a v a r i e t y o f responses f o r t h e s e s p e c i e s under c o n t r o l l e d temperature and moisture conditions. With t h e exception o f AZnus incana and Shepherdia canadensis, a l l species exhibited some r o o t production. With few exceptions t h e r e was l i t t l e d i f f e r e n c e between t h e two r o o t i n g media and t h e wounding and hormone treatments used. The r o o t i n g p o t e n t i a l o f t h e various s p e c i e s , excluding AZnus spp. and S. canadensis, a r e s i m i l a r t o those reported e a r l i e r f o r t h e same o r s i m i l a r s p e c i e s (Bailey and Bailey 1934, Bogdanov 1968, Hartmann and Kester 1975, Holden 1975) Lepisto (1970) reported rooting percentages of up t o 74 percent with AZnus incana and 33 percent with A. gtutinosa. Average success with A . incana was 4 3 percent and A . gZutinosa, 16 percent.

.

Although l i m i t e d i n scope, propagation t r i a l s with r o o t s and rhizomes i n d i c a t e d t h a t t h i s approach should be i n v e s t i g a t e d i n more d e t a i l . These p l a n t p a r t s a r e more d i f f i c u l t t o c o l l e c t ; however, our r e s u l t s suggest t h a t propagation of species,such a s Vacciniwn uZiginosm and Shepherdia canadensis could be more successful using t h e s e m a t e r i a l s r a t h e r than stem c u t t i n g s . With t h e exception o f PopuZus baZsamifera, d i r e c t p l a n t i n g of unrooted c u t t i n g s was not successful. Based on work with similar PopuZus s p e c i e s (e.g., McKnight 1970) and o t h e r Alaskan observations, t h e r e s u l t s with balsam poplar were expected. The almost t o t a l f a i l u r e of SaZix aZaxensis t o survive, however, was unexpected. Previous work with t h i s species had r e s u l t e d i n 2-yr s u r v i v a l o f 55-60 percent (Zasada e t a l . 1977). These previous t r i a l s were with material c o l l e c t e d and planted i n e a r l y May on a coarser textured s o i l . These d i f f e r e n c e s i n success with SaZix a l m e n s i s a r e an example o f t h e range i n success tha.t may occur when unrooted c u t t i n g s a r e planted i n t h e f i e l d . Factors such a s s o i l water content, season o f planting, and methods of c o l l e c t i n g and handling c u t t i n g s a r e c r i t i c a l t o success and must be considered f o r each p l a n t i n g s i t e .

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Holden, V . L . 1975. Propagation o f ArctostaphyZos uva-ursi by c u t t i n g s . I n t e r n a t l . P l a n t Propag. Soc. 25:74-77. ~ u l t t h ,E. 1968. F l o r a of Alaska and neighboring t e r r i t o r i e s . Stanford Univ. P r e s s , Stanford, C a l i f .

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