A Walk in the Woods
When you’re strolling our trails this fall enjoy the golden leaves, their telltale shhhhhh-shimmer and take note of what’s below.
A Favorite of Lovers & Teens
Walking through an aspen stand you’re likely to find initials carved on aspen trunks with date of their carving, “BT + LP 4-ever” and the like. The quaking aspen tree’s soft wood is an easy target for mischief making and while the harm penetrates at a microscopic level it begins on a spectrum visible to the human eye. Though this has been a pastime of hikers and young couples through the decades, we now know more about the aspen tree and we know that carving in it’s trunk is not a good idea. Carving on aspens allows for infection from bacteria, fungus, and pests that can lead to the death of the tree, and impedes the tree’s ability to transport nutrients through its stem.
Aspen are one of the most diseased and infected trees in North America. The bark is not like the bark of a pine tree or Douglas fir or any other conifer. These white trunks don’t have that protective, rough shield to protect the green layer of chlorophyll beneath, which is a delicious meal to many creatures, including a slew of beetles.
A tree can heal some minor cuts by compartmentalizing and forming a callus over time, but not unlike a crustacean shedding its exoskeleton, it’s left vulnerable to infestation during healing. Even if the tree heals, these carvings are permanent marks. Unlike other forms of human vandalism, they can not be removed or cleaned.
Community Clusters
These individual trees often live past our own lifespans, a 100 years or more. Aspen grow in “clones,” or groups of genetically identical trunks. Some stands of clones are thousands of years old and comprise some of the world’s largest and oldest organisms. Disturbances such as wildfires or disease usually prompt clones to send up a slew of fresh sprouts. New growth, however, is rare in Sudden Aspen Death, or SAD, which scientists have been studying over the past two decades.
According to an article in Smithsonian Magazine, foresters noticed that aspen in western Colorado were falling silent in the early 2000s. While the trees have always been susceptible to disease and insect attacks, especially in old age, “this was totally different from anything we’d seen before,” says forester Wayne Shepperd. “In the past, you’d maybe see rapid die-off of one stand out of an entire landscape—it wasn’t really a big deal. But now, we’re seeing whole portions of the landscape go.”
The most extensive is in the hottest and driest areas—low-lying, south-facing slopes. The pattern suggests the region’s extreme drought and high temperatures, both symptoms of global warming, have weakened the trees. This allows for more disease and insect attacks.
New stems aren’t growing back after trees die because drought and heat have stressed the trees. During drought, aspen close off microscopic openings in their leaves. This is a survival measure that slows water loss but also slows the uptake of carbon dioxide, required for photosynthesis. As a result, the trees can’t convert as much sunlight into sugar, causing what scientists hypothesize is the trees absorbing stored energy from their own roots. This eventually kills the roots and preventing the rise of new aspen sprouts, essentially starving to death.
Spread The Word
Next time you are out in the wilderness, use a carved tree as a reason to share this knowledge with friends. Enjoy the cool weather in our mountains this autumn and remember if we put in the effort to save the trees now, we keep it that way for much longer and for more generations to enjoy.