Thursday, 7:45 AM. 33 degrees, wind W, calm. The sky is mostly overcast, and the barometer predicts precipitation.
Contrary to popular perception, winter, when all but evergreens have shed their leaves, is actually as good a time to identify trees as any other. Bark, branch, dormant buds, bud scars, persisting fruit, and even shape of the tree are all good identification characteristics. Unfortunately, most botanical keys, if written by professional botanists, use flower characteristics to “key” out one species from another. This method of identification is unerringly scientific and thorough, but often not practical, especially in the field at all times of the year, and certainly not for the uninitiated. A “dichotomous (cutting in two) key” is a method of separating one thing from another by either/or questions, and is a fine logic tool. A dichotomous key can be established for very practical answering of questions, and here is a basic “key” question which one might use for winter identification of trees: look at the branches of a tree, especially the smaller branches, and ask yourself whether they are opposite each other on the stem they are growing on, or whether they are attached alternately. This is an either/or question that separates one kind of thing from another. If the branches are exactly opposite each other on the stem the tree is a maple, an ash, a dogwood or a horse chestnut/buckeye. If the branches are alternate on the stem, it is something else. Now the next either/or question can be asked, to further “key out” the trees. Are you in the north around the Great Lakes, or further south. In the north, one will seldom encounter dogwood, buckeye or horse chestnut trees, especially in the wild, so out in the woods an opposite branched tree is a maple or an ash, and alternate branches are something else. Then the question may be asked, are the opposite branchlets thick and heavy, with some seeds still attached, or relatively thin and delicate, without seeds? Answer that question “thin and delicate” and you are ready to go out into the woods and select maple trees to tap for maple sugaring, and thus are already a woodsman in the eyes of your friends and neighbors. Remember "Mad Horse”(Maple Ash Dogwood Horse chestnut) and you will be on your way to being an expert. If my maple-sugaring pal Andy Larsen reads this he will again accuse me of tapping a Basswood last winter but I swear it was not me.
Anyway, the accompanying photos are of a maple, an ash, and a poplar. Can you "key them out"?. A pretty comprehensive layman’s tree key has just been published by the National Arbor Day foundation, and is available on their web site at $14,95, and I recommend it for the homeowner and for general tree I.D. There are of course many other practical tree keys available, of one degree of complexity or another. An old timer that I like is Michigan Trees by Charles Herbert Otis, I think still in print, published by University of Michigan Press, it also has a good winter key.
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