Dichotomous Key
Dichotomous Key Activity
BIO 103—Principles of Biology I—Instructor: S. Graham
In this activity, you will be using a dichotomous key found at the LEAF web site to identify an unknown tree. After identifying the unknown tree, you will follow a link from that site to the Silvics of North America web site (USDA Forest Service Northeastern Area - St. Paul Field Office) to collect some information on your tree and fill in the worksheet included with this exercise.
Instructions:
1. Open your web browser.
2. Type in the address for the LEAF web site. (www.uwsp.edu/cnr/leaf)
3. Click on Curriculum & Resources
4. Leaf Tree Identification Tools
5. Online Dichotomous Tree Key
6. Read “What is a Dichotomous Key?” and “How to use this key.”
7. We will be doing exercise #2.
8. Click one of the numbers (1-27) below to identify one of our mystery trees. If you end up with two matching pictures you have identified the tree correctly.
9. Using the images shown in the left hand frame, answer the questions in the right hand frame until you get the pictures in the two frames to match.
10. Once you get the pictures to match – Congratulations! You’ve identified your tree – scroll down to the bottom of the right hand frame and click on the link for Silvics of North America to learn more about your tree.
Silvics of North America - online book/publication with information on around 200 trees (www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm)
Additional resources:
University of Wisconsin-Stevens Point (www.uswp.edu)
LEAF Website (www.uswp.edu/cnr/leaf)
USDA Forest Service Northeastern Area - St. Paul Field Office (www.na.fs.fed.us/spfo)
11. Fill out the worksheet on your tree using the information you found on the website.
Scientific name:
Common name:
Family name: (scientific) (common)
Climate (what range of temperatures and rainfall does this tree grow in):
Size/longevity (height, width/diameter, life span):
Damaging agents (major or most damaging - list a maximum of 5):
Used for (this could be uses by humans and/or animals, plants, or other organisms):