As you look around at the hillsides and mountain slopes of beautiful Colorado, you will notice many trees that seem to be trembling or quaking. These are the glorious aspen trees. The aspen was called “the tree that whispers to itself” by American Indians, because of the way the leaves tremble in the slightest breeze. Not only are these trees wondrous to look at — especially in the autumn months when they start to turn anywhere from golden yellow to glowing red — but they also provide so many resources and services to many of the birds and animals that call this place home.
Aspen groves are home to 55 mammal species and some 135 species of birds. Species ranging from humans to hummingbirds all take advantage of the many services that aspen trees provide. American Indians used to make a tonic tea from the bark, which contains substances similar to aspirin, and the Paiutes and Shoshones drank aspen bark tea to relieve venereal disease. Aspen bark can also act as a sort of record keeper for those animals that visit, as many creatures record their passing on its surface.
Animals such as moose, elk and deer take shelter under large aspen groves, and graze on the tree’s leaves, bark and twigs. Elk and deer also use the trunks to rub off the velvet from their newly grown antlers in autumn, and if you look carefully, you can sometimes find the discarded sheds nestled in the grasses beneath these mighty trees. Black bears are also common visitors to the expansive aspen groves. They munch on berries from the bushes that thrive in the understory and leave large gashes in the soft bark as a way to mark their territory. Aspens also attract our spikey friends, the porcupines. They climb up the trunks and munch on the bark, sometimes killing the tree if they eat the bark that encircles the entire trunk.
Beavers are another species that rely heavily on aspens for a number of things. These toothy rodents eat 2 to 4 pounds of aspen twigs and bark every day and are able to gnaw down a tree that is 10 inches and more in diameter! Beavers can annihilate an entire aspen grove in just a season or so. They stockpile branches and saplings underwater for winter feasting and use them to build lodges and dams. It takes around 20 aspen trees per year to support just one beaver!
With so much use and activity in and around aspen groves, it’s difficult for young saplings to take root. It’s a good thing they can reproduce not only sexually, but asexually as well. While they can reproduce with seeds, the most common way aspens expand their numbers is through cloning by root suckering. To expand their grove, an existing aspen tree will send out “suckers” from the original root stock and new trees spring up. Because of this, they are the most widespread tree species in North America and may be among the oldest, because of this amazing ability to clone. Some cloned clumps are estimated to be 10,000 years old, and some may predate the last ice age.
With so many different creatures depending on the aspen forest, you might wonder how you can enjoy these magnificent trees. Well, it’s prime time for us to enjoy their fall color change. You may have noticed a few lone golden trees already. By the fourth weekend in September, we should be well into the peak of the High Country color change with whole mountainsides being illuminated in a warm yellow glow. Some will even fade into salmon and red hues. So when you find yourself meandering in an aspen stand enjoying the striking fall foliage, stop and appreciate the homes they provide and the medicines they provide, because without them, who would survive?
Kayla Kramer works as a naturalist at Walking Mountains Science Center. She enjoys gaining new knowledge about the local ecology, spending time in the wilderness and romping around on the mountains whenever possible.