Using A Dichotomous Key To Identify Trees

Research Questions:

• What is the difference between coniferous and deciduous trees?
• What is a dichotomous key?
• How can a dichotomous key be used to identify trees?

The world is full of a variety of trees. Some trees keep their leaves or needles all year long. These trees are called coniferous. Other trees, called deciduous, lose their leaves. Once a tree is identified as either coniferous or deciduous, a dichotomous key can be used to further identify the tree. A dichotomous key includes a sequence of choices that can be followed in order to lead to the correct name of a tree.  

Materials:

• An assortment of different tree leaves and pictures of the trees they came from OR you can complete this activity as you hike through the woods. 
• A dichotomous key-You can purchase a dichotomous key book at your local bookstore or you can use one of the following online keys…
  • This one is very user friendly-http://www.uwsp.edu/cnr/leaf/Treekey/tkframe.htm
  • http://dnr.wi.gov/org/caer/ce/eek/veg/treekey/index.htm
  • http://www.uwsp.edu/cnr/leaf/Adobe/Key.pdf 

Experimental Procedure:

1. In order to correctly identify trees, you will need to see the leaves and the branches of the tree. You can either do this by collecting leaves and taking pictures of the trees they came from OR simply go on a nature hike taking a printed dichotomous key along with you.
2. Once you have chosen a tree, decide if it is deciduous or coniferous.
3. Follow the steps of the dichotomous key to identify your tree. Repeat this with as many different trees as you can find. Record your observations and identifications in a chart like the one below.

Terms/Concepts: Coniferous; Deciduous;  Dichotomous key; Compound leaves; Simple leaves

References:

1. 1. http://www.uwsp.edu/cnr/leaf/Treekey/tkframe.htm
   2. http://dnr.wi.gov/org/caer/ce/eek/veg/treekey/index.htm