This post is about bark.
I know what you’re thinking. “Bark—an enthralling topic!” I couldn’t agree more, but bark is often overlooked and ignored by most people. Yet bark records many events in a tree’s history.
Thin and smooth barked trees like quaking aspen (Populus tremuloides) are especially good at recording animal sign. Aspen is the most widely distributed native tree in North America. Its bark becomes thick and furrowed only on old trees, and usually only near the ground. Most of the time aspen bark is smooth, colored white to gray (even greenish on young trees) with dark chevrons where self-pruned branches fell to the ground.
Since aspen bark is thin-skinned, it’s easily scarred. Along hiking trails, you’ll commonly find names and initials carved into it. (Don’t do this. No one cares if you were there with your “true love,” who you probably dumped the week after, and it opens the tree to possible infection.) Aspen bark records more than human impulses though. In bear country, you can often find evidence of bears climbing the trees.
Black bears are particularly adept at climbing trees. Their strength and relatively short, sharply curved claws help them gain purchase even on smooth barked trees like aspen. If I’m in an area where black bears live, I almost always look for bear claw marks on aspen. In the Stehekin Valley, bear claw marks are easily seen on aspen along the Stehekin River Trail and Agnes Gorge Trail.
The claw marks represent a moment in time. Under what circumstances were they made? Was a bear startled by a person? Another bear? Was it simply playing or exploring? Black bears are omnivorous, but I have read no records or seen any signs of them eating any part of aspen trees, so they probably weren’t climbing the tree for food. In the eastern U.S. though, black bears often climb another smooth barked tree, American beech (Fagus grandifolia), to feast on beechnuts.
The next time you find an aspen, take a closer look at its bark. Bark isn’t as static as its outward appearance suggests. You might find a story there.