Hackberry



Here on Snow Mountain, in the Blue Ridge Mountains of Virginia, I see quite a few hackberry trees, Celtis occidentalis. Most are trees with circumferences of 5 inches or smaller, trees that have not been around long. Their small size may be, in part, because the forest up here is a young forest. Back in the 1950s and 1960s the mountainsides were farmland—no forests. Farm families had a tough existence along the Blue Ridge, with loads of rocks to deal with, and difficulty getting up and down the very steep, dirt roads. Time marches on, and now there is forest up here and very few people.

The hackberry tree is a favorite of mine, simply because of its bark. This bark is what first brought the tree to my attention. It looks like a topographic map, in 3D, warty and corky. I frequently do work in Shenandoah National Park, on the Buck Hollow Trail, and get to see larger, more mature hackberry trees at that location.

Hackberry trees are native to North America. Given favorable conditions, one of these trees could live to be 150 or 200 years of age. They grow to be medium sized trees, 60 or 80 feet tall or taller, depending on the soil and moisture conditions. They tolerate pollution, although only occasionally are they used as a street tree.

The trees’ berries are edible, though I seldom notice them. Summer brings the berries a red-orange color, which turns to dark purple in the fall. Birds love them.

Looking much like a berry, what I do notice, and use as an identifier, are galls that seem to always be on some of the branch tips or just below the leaf on the petiole.

The galls are the home to young nymphs of an insect—the petiole gall psyllid. These insects and their galls do not do major harm to the tree.

Along with the wildlife benefits of the berries, the hackberry tree is also the larval host to question mark, mourning cloak, and American snout butterflies. It is also the nectar source for several other butterflies and moths.

The photograph, above, is of an American snout, who alighted on my camera strap last summer, as I was hiking. A chance encounter with another admirer of the hackberry tree!

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