Introductory
SPECIES: Salix arbusculoides | Littletree Willow 



ABBREVIATION : 
SALARB

SYNONYMS : 
NO-ENTRY


SCS PLANT CODE : 
   SAAR3


COMMON NAMES : 
   littletree willow
   peachleaf willow


TAXONOMY : 
The currently accepted scientific name for littletree willow is Salix
arbusculoides Anderss.  Recognized varieties are as follows [3,5]:
                 
          S. arbusculoides var. arbusculoides
          S. arbusculoides var. puberula Anderss.
          S. arbusculoides var. glabra Anderss.


LIFE FORM : 
Tree, Shrub

FEDERAL LEGAL STATUS : 
No special status

OTHER STATUS : 
NO-ENTRY


COMPILED BY AND DATE : 
Lora L. Esser, July 1992


LAST REVISED BY AND DATE : 
NO-ENTRY


AUTHORSHIP AND CITATION : 
Esser, Lora L. 1992. Salix arbusculoides. In: Remainder of Citation

DISTRIBUTION AND OCCURRENCE
SPECIES: Salix arbusculoides | Littletree Willow 



GENERAL DISTRIBUTION : 
Littletree willow occurs in central Alaska, the Yukon Territory and
adjacent Northwest Territories eastward throughout the boreal forest to
Hudson Bay.  It extends southward in the eastern Rocky Mountains to
northeastern British Columbia, northern Alberta, Saskatchewan, and
Manitoba.  Littletree willow does not occur in the contiguous United
States [2,3,25].


ECOSYSTEMS : 
   FRES11  Spruce - fir
   FRES19  Aspen - birch
   FRES20  Douglas-fir
   FRES26  Lodgepole pine
   FRES44  Alpine


STATES : 
     AK  AB  BC  MB  NT  SK  YT


ADMINISTRATIVE UNITS : 
     DENA  GLBA  LACL  WRST  YUCH


BLM PHYSIOGRAPHIC REGIONS : 
NO-ENTRY


KUCHLER PLANT ASSOCIATIONS : 
   K012  Douglas-fir forest
   K052  Alpine meadows and barren


SAF COVER TYPES : 
   201  White spruce
   202  White spruce - paper birch
   203  Balsam poplar
   204  Black spruce
   210  Interior Douglas-fir
   217  Aspen
   218  Lodgepole pine
   251  White spruce - aspen
   252  Paper birch
   253  Black spruce - white spruce


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Littletree willow is one of the most common early seral willows that
dominate or codominate communities along streams and rivers in interior
Alaska. Published classifications describing littletree willow as a
dominant or codominant in community types are listed below:

    Subarctic community types of the Northwest Territories.  [20]
    Upland boreal community types of the Northwest Territories.  [9]

VALUE AND USE
SPECIES: Salix arbusculoides | Littletree Willow 



WOOD PRODUCTS VALUE : 
Littletree willow is one of many willows that produces the "diamond
willow" pattern on their trunks.  These willows are carved into canes,
lamp posts, furniture, and candle holders [36].  However, the small size
of littletree willow makes it unsuitable for timber harvest [36].  Carey
and Gill rated Salix spp. value for firewood as fair [7].


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Littletree willow is an important browse species for moose, deer,
caribou, snowshoe hares, beavers, small mammals, and some birds
[15,16,28,29,31,42].  In young, seral communities in Alaska, moose in
the winter feed primarily on willow shoots, quaking aspen (Populus
tremuloides), paper birch (Betula papyrifera), and balsam poplar
(Populus balsamifera) [28].  Of these plants, willow is considered the
most preferred by moose, and littletree willow the most preferred willow
[28,29].  In one study willows accounted for 94 percent of the biomass
consumed by radio-collared moose during observed foraging periods, with
littletree willow comprising 14 percent of total biomass consumed [32].
Snowshoe hares also utilize Salix spp. a great deal in interior Alaska,
occasionally showing a preference for littletree willow [31].
 


PALATABILITY : 
Littletree willow is highly palatable to moose [29].  On fertile sites,
littletree willow has a high nutrient content which can contribute to
the palatability level [29].  Littletree willow is comparatively
unpalatable to showshoe hares when other species are available [6].
Willow palatability increases as the season progresses [29].


NUTRITIONAL VALUE : 
Littletree willow is rated as fair in energy value and fair in protein
value [28].  Protein content for littletree willow at the Kenai
Peninsula study areas during the winter was 4.2 percent [28].

Nutrient composition of littletree willow consumed by moose in the
winter in Denali National Park, Alaska, was as follows [32]:

gross energy: 5.03 kcal/g
% in vitro digestible organic matter: 40.9
% of dry matter crude protein: 6.8
lignin: 15.4 
ash: 1.5
ether extract: 8.4



COVER VALUE : 
Littletree willow characteristically produces dense thickets along
streams and rivers, which provide cover and protection for many avifauna
and mammals.  These thickets also provide shade for fish in streams and
ponds [1,36].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Littletree willow is useful in stabilizing streambanks and providing
erosion control on severely disturbed sites [15].  Littletree willow
successfully colonized local seismic lines in the Northwest Territories
and borrow pits in continental tundra regions of northwestern Canada
[19,20].  Littletree willow was found to be a poor colonizer of crude
oil spills; plant recovery and establishment was extremely slow on these
spills [18].


OTHER USES AND VALUES : 
Native Americans used the flexible willow stems for baskets, arrow
shafts, scoops, and fish traps.  Willows also provided medicine for a
variety of ailments such as diarrhea, indigestion, cuts, and worms [21].


MANAGEMENT CONSIDERATIONS : 
Littletree willow is an important browse source for moose in Alaska.
When assessing moose range conditions only the amount of browsing
sustained by the highly and moderately preferred willow species, such as
littletree willow, should be considered.  Where these species are
overutilized, certain nonpreferred species will scarcely be touched by
moose [29].
 

BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix arbusculoides | Littletree Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Littletree willow is an erect shrub 10 to 15 feet (3.3-4.5 m) tall or a
small tree 25 to 30 feet (7.5-9 m) tall [2,5,17,37].  Twigs are slender
and many branched, and are thinly hairy to hairless depending on age
[5,36].  The bark is gray to reddish brown and smooth [5,37].  The
leaves are green and hairless above and white and finely hairy beneath
[37].  The mature leaves are 1 to 3 inches (2.5-7.5 cm) long.  Roots of
littletree willow are shallow.  Catkins are small and slender on short
stalks [5,37].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual reproduction:  Male and female flowers are borne in catkins on
separate plants.  The fruit is contained in a capsule that splits in
half to release many seeds that are then dispersed by wind or water
[15].  Optimum seed production is reached when trees are between 2 and
10 years of age [15].  The flowers are mostly insect pollinated, with
bees playing the most important role [11,15].  The seeds of littletree
willow are short-lived and nondormant, and germinate immediately on
moist surfaces [10,44].  The broad temperature range of germination for
these seeds, 41 to 77 degrees Fahreneheit (5-25 deg C), appears to be a
compensatory mechanism for the short seed life [10,44].  Germination
occurs best in moist, exposed mineral substrates that receive
substantial sunlight [15].
 
Vegetative reproduction:  Littletree willow will sprout from the root
crown or basal stems [8,16,].  It is also capable of vegetative
reproduction by underground rhizomes or roots [38].


SITE CHARACTERISTICS : 
In Alaska and northern Canada, littletree willow is found in both upland
and lowland forests.  It grows in the open tundra above timberline,
along riverbanks and streambanks, and on floodplains.  In interior
Alaska, it forms dense thickets in riparian habitats, and grows as small
shrubs in white spruce (Picea glauca) and black spruce (P. mariana)
woodlands and in black spruce muskegs [3,5].

Soils:  Littletree willow grows best in deep, moist alluvial bottomlands
but is found in a wide variety of substrates.  The general pH range of
the soil for willows is 5.5 to 7.5 [15].  Growth of littletree willow is
reduced when water levels are maintained at or above the root collar for
extended periods [15].

Plant associates:  Littletree willow is commonly associated with the
following species:  black spruce, white spruce, paper birch, aspen,
resin birch (Betula glandulosa), Cladonia lichens, alder (Alnum crispa
and A. tenuifolia), willows (Salix scouleriana and S. bebbiana), grasses
(Calamagrostis canadensis and Carex species), mosses (Polytrichum spp.),
and herbs (Epilobium spp.) [4,26,37].
  


SUCCESSIONAL STATUS : 
Obligate Initial Community Species
Facultative Seral Species

Littletree willow is a common early seral species that will invade fresh
alluvium deposits, glacial outwash, and silty-sandy alluvial deposits
[1,39].  It is a common species after fire in open stands of black
spruce in wet sites, and is one of the most successful colonizers in
other types of disturbed areas such as roads, borrow pits, bladed
slopes, and mine sites [9,19,36].  Littletree willow can become
established during periods of low water on floodplains but are usually
swept away by high water later.  Once they are well established they can
withstand both flooding and silting and can slow down river flow [39].
Littletree willow has low shade tolerance and cannot persist on sites
that are heavily forested [39].


SEASONAL DEVELOPMENT : 
Littletree willow flowers from April to early August [44].  The fruit
ripens shortly after flowering; seed dispersal occurs form early to
midsummer [16].
  

FIRE ECOLOGY
SPECIES: Salix arbusculoides | Littletree Willow 



FIRE ECOLOGY OR ADAPTATIONS : 
Littletree willow is a fire-adapted species that can sprout from the
root crown and roots [33].  Its small, light seeds are easily dispersed
by wind, and are important in colonizing burned areas [26,33].

  


POSTFIRE REGENERATION STRATEGY : 
   Tree with adventitious-bud root crown/root sucker
   Rhizomatous shrub, rhizome in soil
   Secondary colonizer - off-site seed

FIRE EFFECTS
SPECIES: Salix arbusculoides | Littletree Willow 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire will kill aboveground parts of littletree willow.  High-severity
fires that remove the soil organic layers can destroy the basal
sprouting ability of this species [24].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Littletree willow is one of the most common willows on recent burns in
interior Alaska [36].  Invasion by willows after fire depends on the
season and severity of fire, weather, and presence of a mineral soil
seedbed [38].  In young black spruce stands originating following fire,
littletree willow regenerated at about 4,000 to 5,000 stems per acre
(9,880-12,350 stems/ha) [27].  The chance of littletree willow
establishing years after a fire lessens as the available mineral soil
seedbed sites are occupied by the faster growing herbaceous species or
mosses [38].  Littletree willow is the dominant species following fire
in black spruce communities for 6 to 25 years [38].
 


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Fire severity can affect willow postfire recovery.  High-severity fires
can damage the roots and rhizomes to the point of no recovery [38].
Following low-severity fires most willows will recover quickly due to
the ability of the root crown to send up new roots.  Severe fires that
destroy the organic soil layer kill willows but can expose the mineral
soil necessary for seed propagation [24,38].


FIRE MANAGEMENT CONSIDERATIONS : 
Prescribed fire is a common wildlife management tool used to rejuvenate
decadent littltree willow communities.  Fires increase food for
herbivores dependent on browse plants.  Browse plants such as littletree
willow and other willows proliferate in early postfire seres [23,36].

REFERENCES
SPECIES: Salix arbusculoides | Littletree Willow 



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Related categories for Species: Salix arbusculoides | Littletree Willow