Focus:
The student will learn to identify trees by using a dichotomous key. This is a good classroom activity in preparation for Activity #10 at the Starker Forestry Trail.

Materials:
• Leaf key
• Leaf worksheet
• Pencil

Procedure:
Ask the class if anyone can name a type of tree. Then ask the student to give some specific characteristics of the tree they just named.

Ask the class if anyone has any idea how foresters identify trees. Introduce the term dichotomous key. Explain that the word dichotomous comes from two Greek words that, together, mean “to divide into two parts”. A dichotomous key is based on the idea of making a choice between two alternatives.

Hand out the leaf key and the leaf worksheet. Have them focus on the leaf key. As they start from the top, each number will give them two phrases that describes the leaf (or leaves) being keyed out. They need to choose one of the two phrases that accurately describe the tree leaf they’re trying to key out. That phrase will either direct them to another set of phrases or give them the name of the tree the leaf grows on. Let the class try to key out the nine leaves on the worksheet.

After everyone has completed the worksheet, go over the answers with the class.

(This activity and the worksheets are from Ranger Rick’s Nature Scope: Trees are Terrific! Volume 2, Number 1, 1985.)