This aspen tree is a fairly old one. It has bear claw marks running up its trunk from bears climbing it.
This aspen is growing in a canyon at high elevation.
The quaking aspen, named for the way its leaves shimmer in the breeze, grows at very high altitudes. It multiplies most often by cloning itself through its root system and thus is often observed as a small stand of several trees instead of one individual tree. One can tell individual aspen organisms, each composed of a root system and many stems, by looking at when they flower in spring or change color in fall (all the stems will change at the same time). An individual "tree" lives only for a few decades, but the root system can live for much longer. Aspens play an important role as "pioneer trees" - they are the first trees to reclaim open land after a fire. They then provide shade for other trees, like spruce and fur, to take over and replant the original forest. The aspens like a lot of light, so they then die back to return after another fire.