The aspen trees we see are the
above ground portions of the clone. Aspen are intolerant and
need full sunlight to prosper. They are a relatively weak
tree that is easily damaged by fungi or killed by fire. When
the overstory aspen trees die, a hormonal imbalance develops
in the root clone, which induces sprouting of the tree. Often
tens of thousands shoots per acre will sprout.
It’s a good thing that so many shoots
are formed because grazing animals love aspen. Shoots are
preferred forage in the winter months by big game as well
as domestic livestock. Some shoots do grow beyond the reach
of the animals and again form the aspen forest we see.
Aspen trees are in decline however, and it
is estimated that Montana has lost 64% of its aspen groves.
The culprit is a lack of fire and overgrazing. Fire suppression
has allowed conifers to spread into aspen groves where they
shade the aspen. Since it is intolerant, the aspen begins
to decline. Fire suppression also means that the above ground
aspen are not killed, so the clone does not sprout. Aspen
trees are short lived and need the sprouting response to keep
the clone healthy. As the above ground aspen decline in health
so does the vigor of the clone and this creates a cascade
effect in the tree’s decline. As the clone becomes weaker
the sprouts are fewer and grazing animals have more of a negative
effect on the tree.
The bark of
the aspen is smooth and white. There are dark scars on the
bark where branches have died back. The leaves
of aspen are round, and about an inch and a half in diameter.
Aspen bloom in the spring and produce cotton like seeds
In some parts of the country aspen is used
for wood pulp. In Montana, the tree is reserved for the beauty
it bestows on our landscapes and for the diversity of life
it fosters.
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