26 NEBRASKAland • OCTOBER 2016
in the world. Made up of 40,000
individual trees, Pando, Latin for "I
Spread," covers about 106 acres on the
Fishlake National Forest in Utah and
weighs an estimated 13 million pounds.
While individual trees can live about
150 to 200 years, Pando is estimated
to be 80,000 years old. As older trees
die, they fall and make room for new
sprouts. The clonal growth makes it
difficult to contain or kill the tree,
which is considered a weed in some
portions of its range.
A pioneering, early-successional
species, aspens grow in a variety of
soils from sand to rock, doing best
in moist soils, and require plenty of
sunshine. They readily colonize areas
disturbed by fire or other means. Those
same disturbances help maintain a
stand, which will respond with a flurry
of suckers, the strongest of which weed
out the others to become trees. While
aspens can dominate an area, they
are often replaced by shade-tolerant
conifers like pines, which eventually
will shade out the aspens.
Ice Out
Two million years ago, glaciers
covered the eastern quarter of
Nebraska, as evidenced by the boulders
that litter the countryside. But it was
the end of the last Ice Age and the
Pleistocene epoch to which Nebraska's
aspens can be traced.
The Wisconsonian Glaciation, the
last advance of the Laurentide Ice
Sheet that began 85,000 years ago,
covered all of Canada and most of the
northern United States, barely crossing
Nebraska's northeastern border.
Nebraska was a much colder place
then. Forests here, and in points as
far south as Texas, were dominated
by spruce and other species that now
comprise the boreal forest that spans
A stand of quaking aspen grows beneath a cliff along West Ash Creek in the Nebraska National Forest near Crawford.
