Terms appearing in bold print may be found in the Glossary of Tree Terms.
Identification of trees is basically a process of elimination. When confronted with a tree you are not familiar with, first ask the following questions:
- Is the trunk straight?
- Is the trunk single-stemmed?
- How do the leaves, flowers, and fruit look?
- For example, the tulip tree has a straight, single stemmed trunk; the leaves look as if someone had taken a pair of scissors and trimmed the tops into widespread notches; the flowers look like tulips and the fruit looks like a little, dry pineapple.
- Look for leaves of different shapes – unlobed, two lobes, three lobes?
- Examine the twigs and inner bark – notice any odor?
- Does the tree bear thorns and are they large and branched, or small and borne singly or in pairs?
- Broadleaved trees – are the leaves borne oppositely on the twigs or alternately?
- Which ones have simple leaves (a single leaf on a leaf stem) and which have compound leaves (a number of leaflets on a leaf stem) or doubly-compound leaves ( a number of leaflets on a leaf stem which branches)?
- Parts of a Tree – diagrams and descriptions of leaves and arrangements
- Does the tree bear needle or scale-like leaves?
By knowing a few simple facts, we can place trees in small groups and then make a positive identification by knowing one or two additional facts about each individual tree.
Identification Chart for Broadleaved Trees
Suppose you find a tree with compound leaves, alternately arranged on the twigs. To use the chart , take the top, or ALTERNATE path. Then take the path marked COMPOUND. The first tree on this path, black locust, has 7 to 17 leaflets and small thorns, arranged in pairs. Your tree has seven to nine leaflets, but it has no thorns, so you go along the path. Finally, you come to a tree, bitternut hickory, which has seven to nine leaflets and yellow buds. You examine your tree again, and find it has yellow buds. So you turn to the complete description of bitternut hickory in a tree identification book and compare your tree with it. The description fits, so the identification is complete.
The next tree has compound leaves arranged oppositely on the twigs. This time, you take the bottom, or OPPOSITE path, then the path marked COMPOUND. The first tree on this path has three to five leaflets on green twigs. Your tree has these characteristics, so you turn to the page containing the complete description of boxelder and compare your tree with it. The description fits, so you are sure that your tree is a boxelder. Since 29 of the 43 trees on the chart have simple leaves, alternately arranged on the twigs, the top path is the most difficult to follow. Long leaf stems are 1½ to 2 inches in length or longer. Those of redbud and basswood are usually 1½-2 inches long, and those of aspen and cottonwood are usually somewhat longer; while those of the other three are considerably longer (sycamore 2½-5 inches, tulip tree and sweet gum 5-6 inches).
Of the 13 trees indicated as having short leaf stems, 12 have stems considerably less than one inch long (most ½ inch or less), and one, black gum, occasionally attains one inch.
If you should happen to get lost in this path, try the “shotgun method”. Scan this part of the chart for a set of characteristics which fit the tree you are trying to identify.
Many trees show preferences for certain kinds of growing conditions such as wet situations.
The most common tree community in Indiana is the oak-hickory association which occupies more than half of the forest land in the state. Next most frequent is the beech-maple association – one-third;
Third is the pin oak-sweet gum (10%) – occupies the overflow bottomlands and the more poorly drained soils of southern Indiana.
There is no abrupt dividing line between communities, they often blend into one another, and it is not uncommon to find two or three different communities within one farm woods.
Trees can be related to each other just as people are. For example, all the oaks are very closely related, and the beech is related to the oaks. Hickories are closely related, and are “cousins” to the walnuts. Therefore, because of the relationships between trees, they can be studied in family groups i.e. the Ashes, the Elms, the Hickories, the Maples, the Oaks, trees with needles or scale- like leaves.
Tree Identification in Summer
Broadleaved trees in winter may be identified by their bark, form, and certain features of the twigs (buds, leaf scars, pith, etc.); also by the fruit which a few trees retain far into the winter. But in summer broadleaved trees may be identified primarily by their leaves.
The fruit of some trees is very helpful to identification in summer. Basswood, sweet gum, osage-orange and persimmon fruits are good examples. Other trees, such as beech blue beech, and sycamore, can be identified by their bark.