Wednesday, November 18, 2009

Adirondack Tree Indentification 101

I was a Stumpy – a student at the College of Environmental Science and Forestry. While an undergrad, I was enrolled in the Dual Program: Resource Management (forestry) and Environmental and Forest Biology. A required course for forestry majors, as you might well imagine, was dendrology, or the study of trees, and a huge part of dendro was simply learning to identify one species of tree from the next.

Looking back at my dendro class through the lens of time, I am constantly amazed at how difficult I found tree ID. The tree that gave me the worst trouble was the black cherry, which today I could almost identify blindfolded, standing on one foot, and with both hands tied behind my back. I suspect it was the leaves.

When most people learn to identify trees, they try to learn the leaves, but for the novice, one lobed leaf looks much the same as the next. Red maple or sugar? Maybe it’s striped maple? A serrated, or toothed, leaf looks like any other serrated (or toothed) leaf. Aspen? Cottonwood? Elm? Hophornbeam? Birch? And then what do you do when fall has wreaked its havoc on the trees, leaving the forest naked? How in the world are you supposed to know which tree is which now?

Over the years I have refined my tree ID skills, and today when I teach tree ID, I may touch on leaf shape and form, but I spend more time looking at those parts of the tree that are visible year round: the bark and branches. In fact, I’ve boiled the whole subject down to a series of simple questions that even kids as young as ten are able to follow.

First, take a look at your tree. Is it a conifer (does it have needles) or a hardwood (does it loose its leaves in the fall)? If it is a conifer, we next address the needles and bark. Do the needles turn yellow and fall off in the fall (larch)? Does the bark have blisters that ooze a sticky aromatic resin when punctured (balsam fir)? Are the needles attached to the tree via small “pegs” (spruces)? Maybe the needles flattened and scale-like and the bark looks like a cat’s been using it for a scratching post – that would be a cedar. If you crush the cedar’s needles, they have a beautiful citrus-y scent that is very distinctive.

If said tree is not a conifer, it must be a hardwood (or deciduous). So we look at how the branches are arranged on the tree: are they opposite (like my arms) or do they alternate (like my left arm and right leg)? Very few species of trees here in the northeast have opposite branching, and they are easily remembered by recalling the phrase MAD Cap Horse. MAD stands for Maple, Ash, Dogwood; Cap refers to the family Caprifoliaceae, which are the honeysuckles; Horse is simply horsechestnut. Since honeysuckles are really more shrub-like than tree-like, I usually ignore them as a category. Here in the central Adirondacks we don’t have horsechestnuts, so I delete them as well. This leaves us with MAD.

Around Newcomb, we have only a few species that we can squeeze into the MAD classification. Maples: red, sugar and striped. Ash: white. Dogwood: grey-stemmed, red-osier, alternate leafed.

The dogwoods we have up here are pretty small trees, barely more than shrubs. Their buds look like onions, or the domes of eastern orthodox churches seen in photos from Russia and the Ukraine (well, sort of; flowering dogwood, which we don’t have, has onion-shaped buds, and red-osier sort of does; with a little imagination, so does the grey-stemmed). If you take a look at their leaves, the veins are curved, or arched (arcuate). But if you’re standing in the woods craning your neck upwards to figure out what the leaves look like, you aren’t looking at a dogwood, and so, like the honeysuckles, we can easily eliminate dogwoods from consideration.

The process of elimination as brought our opposite-branched trees down to two possibilities: maples and ashes. If the leaves are still on the tree, and you can see them, this can be a clue. Ashes have compound leaves: each leaf is composed of multiple leaflets. Maples have simple leaves with three to five lobes. But suppose the leaves have fallen off and all you can see is the bark. Not a problem. Take a good close look. Feel the bark. Is it kind of corky? Can you easily stick your thumbnail into it? Does it look like many small ridges that weave in and out of each other? If so, you are looking at the white ash, the tree that sportsmen love, for its wood has been the primary source of such sports equipment as tennis rackets and baseball bats.

But suppose it’s not a white ash that you are staring at. If the branches are opposite, and you’ve eliminated all but the maples, then it must be a maple. Striped maple is easy to identify, for it rarely gets larger than three or four inches in diameter. I’ve seen some specimens that push a six inch dbh (diameter at breast height, which is measured at 4.5 ft. above the ground), but they are not common. Striped maple, true to its name, has white-ish stripes on its smooth greenish bark. Its leaves are large and look a lot like goose feet.

Red maple, well, that’s a tree that likes to have its feet wet. If you are in a lowland area, near a marsh or other wetland, and you see a tree with opposite branching, it is likely a red maple. Its leaves, if you can find one, have three distinctive lobes, all with sharply pointed teeth. The sinuses, or dips between the lobes, are also pointy, forming a nice sharp “v”.

Sugar maple, that tree adored by leaf peepers and pancake-lovers alike, prefers to live on rocky slopes, with its feet away from the water. The bark on a mature specimen is pale grey and kind of looks like it is made from plate armor (sometimes you need to apply a little imagination). Some of the sides of the plates may be peeled away from the trunk of the tree. If you find a leaf still attached to the tree, you will note that it has five lobes, and instead of sharp pointy teeth, it has gentle swoops. The sinuses between the lobes are u-shaped, as opposed to the v-shape of the red maples.

When it comes to the trees that are alternately branched, we are facing a larger selection of species, and I’ll write about them next time. In the meantime, take the information I’ve given you here, grab a kid or two, and head out into your yard. See if you can find some trees with opposite branches and try your hand at identifying them. The next time you go for a hike, see how many opposites you can find. Do they like each other’s company? Can you ferret out other clues that you can add to your ID arsenal?

Once you start to recognize tree species, you will begin to notice other plants (and animals) that associate with them. Forest communities will become apparent. Before you know it, the trees of the forest will seem like old friends, familiar faces you can recognize in any crowd, and I find that hiking with friends makes being outside that much more pleasurable. Perhaps you will, too.


Ellen Rathbone

Ellen Rathbone is by her own admission a “certified nature nut.” She began contributing to the Adirondack Almanack while living in Newcomb, when she was an environmental educator for the Adirondack Park Agency’s Visitor Interpretive Centers for nearly ten years.

Ellen graduated from SUNY ESF in 1988 with a BS in forestry and biology and has worked as a naturalist in New York, New Jersey, and Vermont.

In 2010 her work took her to Michigan, where she currently resides and serves as Education Director of the Dahlem Conservancy just outside Jackson, Michigan.

She also writes her own blog about her Michigan adventures.





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