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Trees of Yosemite (1932, 1948) by Mary Curry Tresidder


Introduction


Identification of the Trees

Identifying the trees means checking up on this detail and that, narrowing down, eliminating—until, gradually, the eye automatically recognizes the salient characteristics, even at a considerable distance.

In her Handbook of the Trees of California, which is, unfortunately, out of print, Miss Eastwood gives a triple means of identification: a key to the trees according to the leaves, one according to the fruits, and one in accordance with the analytical classification into families. For the beginner, the leaf is often the readiest means of identification, as even when the leaves have fallen they may usually be found near by. Of course, due caution must be exercised in such a case.

To turn to method, then: keep the zone in the back of your mind, for that is helpful in limiting the possibilities. If the leaves are linear, either lance-shaped or awl-like, the tree belongs to our first group, the Gymnosperms, which are conifers in the main. If it has broad leaves, it belongs to the Angiosperms.

A chart using the leaf as the key is given for each of these groups. Narrow the problem down by its use; then look up the probable solutions, with the pictures as a guide and a check. You must go through the characteristics until you have the species well before you: the leaf, the bark, the size and appearance of the trunk, the cone (if that is available either on the tree or on the ground), and the situation as regards sun and shadow, moisture and dryness, the kind of soil. The process will sharpen your observation, making you aware of countless details you have never noticed. On the other hand, your mind at length will come to grasp the important things about a tree, and the actual steps in the procedure will be taken without conscious deliberation The very silhouette of a tree is enough for an expert, especially of a tree with such a distinctive outline as the Sugar Pine or the Sierra Juniper.

The difficulty is that the tree does not often conform exactly to type. A typical Ponderosa Pine, for example, may readily be distinguished from a typical Jeffrey; but few are “typical,” and unless the cones are available (the easiest way of identifying the species, in this case) the identification may be hard. To call the foliage age of one blue-green and that of the other yellow-green is likely to be of little avail unless they are side by side, and not always then. One may have a pointed top for a Jeffrey, the other a flattened or rounded top for a Ponderosa Pine. And so it goes; it is essential to check up by every possible means.


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