Aspen
(Populus tremuloides), also known as Quaking, Trembling or
American Aspen are in the willow family, and are medium-sized
deciduous trees.
Growing
conditions
Typically
grow in large colonies from a single seedling, and spreading
by means of root suckers to up to 100 feet away. They are able
to survive intense forest fires as the roots are below the heat
of the fire, and new sprouts grow after the fire is out. They
don't thrive in shade, and it's hard for seedlings to grow in
an already mature stand. Fire indirectly benefits aspen trees,
as it allows the saplings to flourish in open sunlight on account
of the burned landscape.
Uses
The wood is white
and soft, but fairly strong, with low flammability so it's
often used for making matches (easy to blow out, so safer
than most other woods).
Shredded aspen wood is a popular animal
bedding, and won't cause respiratory ailments.
Heat-treated aspen is a popular material
for sauna interiors.
The leaves, twigs and bark are highly
nutritious, and deer and elk use them for overwintering. Black
bears, cottontails, porcupine, and snowshoe hares feed on
bark, buds, and foliage, and grouse and quail eat the winter
buds. Small mammals, such as shrews, mice, and voles love
aspen too, and it's a favored building material of that Ladd
favorite, the North American beaver. Also, the layered structure
of an aspen grove is popular with birds, and snags provide
perches for birds of prey, and sites for cavity nesters.
Fun
Facts
One tradition has it that aspen leaves
are made from female tongues, and their quivering is due to
women's inability to stop talking.
According to Christian lore, the aspen
tree's quivering leaves are the result of arrogance at the
Crucifixion because the aspen did not tremble like other trees.
Lately aspen has become more popular in
forestry because of its fast growth rate and ability to regenerate
from sprouts (regeneration after harvesting is cheaper). Unfortunately,
starting in 1996, some scientists noticed an increase in dead
or dying aspen trees. As this accelerated, in 2004, a debate
over causes began. No insect, disease, or environmental condition
is yet specifically identified as a joint cause.
Size
50-80 feet tall.
Form & Shape
Loose, irregular crown.
Bark
Smooth
white bark.
Leaves
Nearly round leaves on mature trees, 3-6"
in diameter with irregular rounded teeth carried on strongly
flattened leaf stems, which enable the leaves to twist and
flutter in the slightest of breezes. Leaves on seedlings and
root sprouts differ markedly and are nearly triangular and
larger.
The unusual ability of the leaves to twist
and bend is thought to help protect the trees from severe
winds, possibly by helping dissipate energy more uniformly
throughout the canopy. Supposedly it also improves the rate
of photosynthesis throughout the tree by reducing the exposure
of the outer leaves to extreme sunlight by presenting the
leaves at an oblique angle to the sun throughout the day,
while allowing more light through to the lower leaves which
are generally in shade. This would enable leaves throughout
the tree to photosynthesize more efficiently.
Flowers
The flowers are
catkins 1 ½ to 2 ½" long, produced before
the leaves in early spring. Male and female catkins are on different
trees.
Fruit
The fruit is a 4" long
pendulous string of small capsules, containing about ten minute
seeds embedded in cottony fluff. These are easily dispersed
by the wind in early summer.
Life expectancy
Each tree only lives for 40-150
years above ground, but the root system of the colony is long-lived,
in some cases for many thousands of years, sending up new trunks
as the older trunks die off above ground. As a result, it is
considered to be a sign of ancient woodlands (a colony in Utah,
called Pando, is said to be 80,000 years old).
