BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix monticola | Mountain Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Mountain willow is a native, erect shrub 3 to 12 feet (1.5-4 m) tall,
and usually forming dense clumps [3,5].  The trunk of mountain willow is
smooth or slightly cracked, and branches are often pruinose.  The wood
is fine-grained and soft and has no sapwood-heartwood line [8].
Mountain willow has a remarkable characteristic of plasticity; its
growth form adapts readily to a wide variety of habitats [14].
Branching habit and foliage characteristics vary greatly depending on
site conditions [14].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual reproduction:  Mountain willow is dioecious.  The fruit is
contained in a dehiscent capsule that releases many seeds that are then
dispersed by wind or water.  Optimum seed production occurs between 2
and 10 years [14].  The flowers of mountain willow are mostly, but not
exclusively, insect-pollinated.  Bees are the chief pollinating agents
[10,14].  The seeds of mountain willow are short-lived and germinate
immediately on moist mineral substrates with high relative humidity and
in full sunlight [14].  Germination is inhibited on sites with a
continuous cover of tree litter [7,14].  Seed germination occurs over a
broad temperature range, from 41 to 77 degrees Fahrenheit (5-25 deg C).
This appears to be a compensatory mechanism because of the short seed
life [7,41].  This adaptation to a wide range of temperatures is
particularly important in interior Alaska, where surface soil
temperatures may vary over a relatively wide range [41].

Vegetative reproduction:  Mountain willow sprouts readily from the root
crown or basal stem [14,32].  It will root from stem cuttings or root
fragments on moist to wet sites.  Mountain willow will sprout vigorously
following cutting regardless of cutting season, but vigor is more
pronounced if cutting occurs during the dormant season [7,14]. Mountain
willow exhibits early growth from both seed and sprout; but vegetative
reproduction of willow was six times greater than willow growing from
seed on a 6-year-old burn in Alaska [14].


SITE CHARACTERISTICS : 
In Alaska and northern Canada, mountain willow is found in wet areas
such as heaths, riverbeds, and streams [3].  In interior Alaska,
mountain willow occurs in glacial drift and on river floodplains that
are nutrient-rich [14].  The best growth occurs in moist, alluvial
bottomlands, but mountain willow can be found growing on a variety of
substrates.  In the Intermountain region, mountain willow is best
represented in riparian communities within the middle-to upper-elevation
forest of subalpine fir (Abies lasiocarpa) and in the forest-alpine
transition zone above the limit of contiguous forests, dominated by
whitebark pine (Pinus albicaulis) [21].

Soils:  Mountain willow is usually found on moist sandy or gravelly
soils but is adaptable to a wide variety of soils [37].  It will
tolerate moderately alkaline soils but does poorly in extremely acidic
of alkaline conditions.  The general pH range for willows is 5.5 to 7.5
[14].  Growth of mountain willow is severely reduced when water levels
are maintained at or above the root collar for extended periods [14].
Mountain willow is also shade intolerant and grows best in full sunlight
[14,37]. 

Plant associates:  Mountain willow is commonly associated with Booth
willow (Salix boothi), Geyer willow (Salix geyeriana), Drummond willow
(Salix drummondiana), alder (Alnus spp.), river birch (Betula
occidentalis), lichens (Cladonia spp.), bluejoint reedgrass
(Calamagrostis canadensis), beaked sedge (Carex rostrata), water sedge
(Carex aquatilis), rush (Juncus spp.), bluegrass (Poa spp.), and mosses
(Polytrichum spp.) [4,16,29].


SUCCESSIONAL STATUS : 
Obligate Initial Community Species  

Mountain willow occurs in initial to early seral plant communities along
river systems of interior Alaska.  Mountain willow is a pioneer species
that becomes established after disturbances such as fire, logging or
recent alluvial deposits resulting from floodplain processes [39].
Mountain willow has low shade tolerance and therefore loses dominance on
sites that are heavily forested or succeeded by more shade-tolerant
species [14].


SEASONAL DEVELOPMENT : 
Mountain willow flowers in May, before the leaves appear, through July
[34].  The fruit ripens soon after flowering, followed by seed dispersal
in early to midsummer [14,41].
  

Related categories for Species: Salix monticola | Mountain Willow