BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix glauca | Grayleaf Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Grayleaf willow commonly grows as an erect shrub 3 to 4 feet (0.9-1.2 m)
tall.  On exposed tundra sites it grows as a low, semiprostrate shrub,
and on favorable sites it sometimes grows up to 20 feet (6 m) in height
and 5 inches (12 cm) in diameter [35].  The bark is gray and smooth but
may become rough and furrowed on larger individuals.  Male and female
flowers occur on separate plants in 3/4- to 2-inch-long (2-5 cm) catkins
that persist over the summer.  The fruit is a 1/32- to 1/16-inch-long
(0.8-1.6 mm) two-valved capsule [35].

Two growth forms occur in the Rocky Mountains.  In somewhat sheltered
locations in subalpine environments, plants are upright and taller,
while semiprostrate plants that are often difficult to distinguish from
arctic willow (S. arctica) grow in more exposed, alpine situations [10].
 


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Grayleaf willow's primary mode of reproduction is sexual.  It produces
an abundance of small, lightweight seeds.  Like most willows, it
probably begins seed production at an early age (between 2 and 10 years)
[16].  Seeds are not shed as they ripen but remain on the plant
throughout the summer and are dispersed in the fall.  Each seed has a
cottony down which aids in dispersal by wind and water.  Unlike willow
seeds dispersed in summer, grayleaf willow seeds overwinter under snow
and germinate in the spring soon after snowmelt [9,41].  This cold
stratification promotes good germination; seeds germinate over a wide
range of temperatures (from 41 to 77 degrees F [5-25 C]) [9].  Spring
germination is advantageous in arctic and alpine environments; the
growing season of grayleaf willow seedlings is 3 to 6 weeks longer than
that of summer-disersing willows [9].  Exposed mineral soils are
required for good germination and seedling establishment [16].  Forest
litter generally inhibits germination and establishment.

Vegetative Reproduction:  Grayleaf willow sprouts from the root crown or
stembase if aboveground stems are broken or destroyed by cutting or fire
[16].


SITE CHARACTERISTICS : 
In Alaska and northern Canada, grayleaf willow grows on both uplands and
lowlands.  In arctic tundra it often grows along river and streambanks,
on sandy and gravelly floodplains, and on old benches [3,35].  In boreal
environments, it grows as scattered shrubs in white and black spruce
(Picea mariana) woodlands, in black spruce muskegs, and on river
floodplains [3,35].

In the Rocky Mountains grayleaf willow is restricted to open, alpine and
subalpine habitats that commonly have rocky, well-drained soils [10,27].


SUCCESSIONAL STATUS : 
Grayleaf willow is an early seral species.  It pioneers freshly
deposited river alluvium, glacial outwash, and disturbed areas with
exposed mineral soil, such as road cuts and mine tailings [35].  It is
also common in spruce woodlands following fire, especially in stands
about 20 to 30 years old [14,23].  It has been found in 160-year-old
open spruce woodlands [11], but it is usually displaced in densely
forested stands because of its shade intolerance.


SEASONAL DEVELOPMENT : 
Grayleaf willow catkins appear with the leaves.  In Alaska and the
Yukon, flowering generally occurs in June, the fruits ripen in July and
August, and the seeds are dispersed in late August and September [9,35].

Related categories for Species: Salix glauca | Grayleaf Willow