BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Salix lutea | Yellow Willow 



GENERAL BOTANICAL CHARACTERISTICS : 
Yellow willow is a deciduous shrub, or rarely, a small tree up to 23
feet (7 m) tall, with stems diameters up to 8 inches (20 cm) [7,11,44].
The silvery-gray bark of older twigs distinguishes it from many closely
related willlows [11].  The leaves are alternate, simple, pinnately
veined, mostly lanceolate, with finely serrate margins, dark green to
yellow-green above and pale or glaucus beneath, with conspicuous
stipules usually present [7,11,19,44].  Male and female flowers occur on
separate plants as catkins.  Staminate catkins are .8-2 inches (2-5 cm)
long, and pistillate catkins are .8-2.7 inches (2-7 cm) long, but mostly
under 1.5 inches (4 cm) [7,19,37].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
The dispersal of thousands of small windblown seeds is the primary
method that yellow willow uses to reproduce itself.  Male and female
flowers (in the form of catkins) occur on separate plants.  Like other
willows, it probably relies heavily on insect pollination, especially
from bees [31].  After fertilization, a capsule develops which
eventually splits open during spring or summer, dispersing the numerous
tiny seeds.  The production of large quantities of seeds ensures that
some will fall on favorable sites.  The seeds have a cottony down which
allows them to float long distances in the wind, and on water.  Seeds
are non-dormant, remaining viable for only a few days.  They germinate
rapidly, usually within 12-24 hours if a moist seedbed is reached [6].
The seed contains significant amounts of chlorophyll, and photosynthesis
generally occurs as soon as the seed is moistened.

Yellow willow is unable to produce suckers from lateral roots, but will
resprout from its root crown or stem base following fire or cutting
[2,18,19].  Regeneration may also occur through broken pieces of stems
or roots, which are transported and deposited by floodwaters, and later
sprout (this is common in willows) [2].  It is readily propagated from
stem cuttings that root easily in moist soil.  This is covered more
fully under "Value For Rehabilitation of Disturbed Sites".


SITE CHARACTERISTICS : 
Yellow willow is riparian in nature, found growing along stream and
river edges, moist ditches, and moist alluvial terraces [19,44,47].  

Soils:  When growing near a stream or river bank, it is typically found
on coarse-textured soils, but when found on alluvial terraces or moist
benches, it may occur in soils ranging from deep silts to sand [7,19].
In Montana, Hansen and others [19] report that stands adjacent to stream
channels have poorly developed mineral soils overlying coarse substrates.

Elevation:  In the Rocky Mountain States, yellow willow is normally
found at low to mid-elevations.  Elevational ranges for the following
western states is as follows [1,7,20,21,44,46,47]:

from 5,000-9,500 feet (1,524-2,896 m) in CA
from 7,000-8,000 feet (2,134-2,438 m) in CO
below 6,000 feet (1,830 m) in ID
below 7,000 feet (2,134 m) in e OR
from 4,400-7,700 feet (1,340-2,350 m) in UT
below 7,000 feet (2,134 m) in e WA
below 7,000 feet (2,134 m) in WY


SUCCESSIONAL STATUS : 
Yellow willow is generally a pioneer or early seral species when
occurring along streambanks subjected to periodic flooding [19].  But
stands on moist benches with well developed soils may be long-lived
[47].  If conditions become permanently drier on these benches, stands
may be replaced by communities dominated by grasses such as tufted
hairgrass (Deschampsia caespitosa) and Kentucky bluegrass (Poa pratensis)
[19].


SEASONAL DEVELOPMENT : 
Yellow willow is a deciduous shrub or rarely small tree.  Its catkins
emerge before and with the leaves in the spring.  After fruits ripen,
seeds are dispersed from spring to early summer [6].  In California, it
flowers from May to June [22].  The flowering times for Salix rigida
(which is taxonomically similar to yellow willow) in the following
western states are presented below [9].

Flowering Begins      Flowering Ends     State

    May                   June            CO
    May                   May             ND
    April                 June            UT
    May                   August          WY

Related categories for Species: Salix lutea | Yellow Willow