Wildlife Wednesdays — Aspen Trees After the Fire

By Andy Ames

New Aspen trees are thriving after the East Troublesome fire of 2020. Aspens trees are pioneer species and require disturbances like fires to survive. Aspen groves are colonies of trees all connected through a common root system. Each tree is a clone of the others. While individual Aspen trees are relatively short lived (generally less than 100 years) Aspen groves can live for thousands of years. In the right conditions, Aspens can reproduce by seed, but most commonly they reproduce by sprouting from the root system of the grove. Aspen sprouting is controlled by growth regulators (similar to hormones). Cytokinin is produced in the roots and promotes sprouting while auxin, produced in the branch tips, suppresses sprouting. So, when a fire passes through an Aspen grove, hot enough to even kill existing trees, the auxin suppressant will be cut off, this spurring a flurry of new growth.

New Aspen growth beneath the burned trunks from the East Troublesome fire. Even though these new sprouts are clones of the old tree their leaves are substantially larger. This additional surface area of the new sprouts allows for even faster growth.

In less than two years the new trees are already several feet tall in places.

All this new growth creates wonderful wildlife habitat.

This was taken last fall. Even then the new growth of Aspen and other vegetation provided nourishment for moose and many other species.

Aspen trees are even able to photosynthesize through their bark. This has the benefit of providing extra energy in shady environments but with the downside of being good nutrition for elk and moose. The thin bark also provides little fire protection.

Last year’s new sprouts emerging just months post fire.

This was taken from the same spot as the second picture one year before. Note the amazing growth that occurred in just one year!