Explorers

In October 2009 the Explorers learned how to use a pocket guide to identify tree leaves.

The group started by practicing together on a leaf that Mr. Ramsey showed. They learned that the first step is to determine whether the leaves grow from the branch in alternate patterns (like steps, one on each side) or opposite (with each leaf having a partner coming out at the same spot but on the other side). Next comes the question of whether the leaves are simple or compound. Simple leaves have one basic leaf shape or “unit” coming off of each leaf stem—they may be round or straight or any sort of weird shape, but there is only one leaf body per stem. Compound leaves, on the other hand, have multiple “leaflets” coming off of each leaf stem. These may look like individual leaves, but the key is to examine whether they are coming off a branch (brown and stiff and woody) or a stem (lighter colored and flexible).

With those things in mind, the group started working in pairs to identify a series of mystery leaves that Mr. Ramsey provided. The Explorers discovered that once those initial basic questions have been answered, identifying the leaf depends on proceeding through a series of further questions that increasingly narrow down the possibilities. Things that must be taken into account are the presence or absence of “lobes” (parts of the leaf that stick out in a distinct pattern) and teeth (generally small and ragged along the edges), the number and pattern of veins, the general shape of the leaves, and their size. Two or more different leaves may share most characteristics, so each of these things must be considered.

The Explorers also learned that most trees and their leaves belong to certain “families,” such as maples, oaks, beeches, and so on. The leaves within a family generally share many features, and it can be particularly difficult to distinguish between some of them.

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The student pairs struggled with the first few leaves they examined, but by the end of the session most of them were having much more success at correctly identifying the species or at least the family. We are planning to continue this practice in the “wild” during our upcoming fall hike.

To see some photos of our leaf identification session, check out the Gallery.

NOTE: We used small leaf identification books to figure out our leaves. The link below is to a web site that uses a similar system to identify trees.

Tree Identification