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].
  

Related categories for Species: Salix arbusculoides | Littletree Willow