The big tulip tree in the front yard has beautiful bark. Like most mature trees, its bark has deep furrows or cracks, but is smooth in between. The fractures in the corky bark surface interconnect like chains in a wonderful pattern. On the widest part of the trunk, next to the ground, lichens and mosses give the bark a green tinge. Further up the tree the bark becomes smoother and shows scars where old limbs have broken off. Triple rows of horizontal dots here and there reveal scars that remain on the bark where sapsuckers, those sap-sipping winter woodpeckers, drilled though the bark in seasons past.
It is fun to “read” a tree, to see its bark tell the story of its life. A swollen knob in the bark or a ragged stump shows where a limb was violently broken off. A lightning scar down the trunk tells of past storms. Distinctive elbows and turns in limbs result where twigs broke off while the tree was young. Strange growths or circular bark patterns show the effects of disease. Dead limbs, insect and woodpecker workings, and peeling bark betray that a tree is stressed or dying.
As a naturalist, I’ve studied the color and patterns of tree bark for many years. It’s gotten to the point where I can generally identify a tree in winter by looking at its bark, although this isn’t always easy. The bark on the same species of tree can look very different depending on the tree’s health, age, and surroundings.
As an artist, I find late winter is the best time to look at the lines, colors, textures, and shapes of trees. Drawings of tree trunks run the gray scale from nearly white to nearly black. Textures vary from paper smooth to a craze of cracks, channels, and fissures. Sunlight and shadow create a tremendous range of colors, even on the same tree. Yet, almost invariably, most artists, whether aged six or sixty, start off making tree trunks brown. I tell them a brown tree is like a green alligator—everybody thinks it should be that color. But go out and really look at a real one. You might see things differently.
In 2013 appeared a wonderful field guide, illustrated with photographs. It shows how to identify winter trees in the Eastern United States by bark alone. Bark, A Field Guide to Trees of the Northeast, by Michael Wojtech, explains how most trees start out with smooth bark. As they grow bigger, they reach a point where the inner wood grows faster than the protective, outer bark. The outer bark layers then crack and separate into plates in ways that are very distinctive according to species. Scalding sun, rodents, insects, fungus, disease, lightning, wind, and fire can also drastically change an individual tree’s appearance as it weathers the ravages of time.
But this month, the biggest tree story is going on unseen, beneath the bark. Lengthening days have caused the “sap” to surge upwards from the roots, to the limbs and twigs. Combined with sunlight, the tree’s living fluid makes twigs color up and buds swell. Look up now and you’ll see the tiny flowers on maples, elms, and a few other trees. For them, spring is already here.By Doug Pifer