RESOURCE SUMMARY: This activity/lesson centers around a dichotomous key published by the BLM of the most common trees and shrubs found in the Cascade-Siskiyou National Monument. In this activity students learn how to use a dichotomous key and then use it as a tool to identifying trees and shrubs in the Cascade and/or Siskiyou mountain ranges.
a) LEARNING :OBJECTIVE: After instruction and practice students will be able to identify native trees and shrubs of the Cascade-Siskiyou Mountains using a dichotomous key.
Before giving students a dichotomous key to use some pre-teaching must take place.
Pre-Teach: Using examples, teach terms associated with the key.
toothed edges of leaf,
needle or scale-like,
bundle of needles.
I taught the terms using actual leaves and some pictures. The students picked up on the terms quickly and were eager to get out of the classroom and find out about the trees and shrubs in and around Canyonville School.
NOTE: See pictures on web-site for more key terms.
Next show students how to use a dichotomous key to identify trees or bushes by identifying a tree and/or shrub sample in the classroom using the step by step method of the key.
I then put students into teams of 2-3 and went to a location where trees and shrubs can be found. I used Canyonville Elementary/Middle School as there are a number of different species found on campus.
I then took each class to Pioneer Park in Canyonville on the second day of the activity to identify more native trees and shrubs.
We also identified a few plants while walking to and from the park.
ASSESSMENT: Students worked with a key on their own to identify 5 different species of plants.
This activity took five days to complete: Two days in the classroom teaching terms and practicing, two days in the field actually doing identification and one day doing an assessment.
c) ASSESSMENT OF EFFECTIVENESS:
This activity took a lot of preparation time. First I had to find an area to do this activity. I did a survey of the plants and trees at Canyonville School and determined that there was enough variety to do the activity on site. Another location I found a good variety of native plants was at Pioneer Park in Canyonville, so I took my students to this location on the second day of the activity. I also had to collect samples for classroom instruction and to make enough copies of the key and pictures for all the students. ( After doing this activity I recommend giving each student a copy of the key instead of just one key per group, as some were unable to get the experience of actually using a key, due to their peers not sharing it. ) Most of the students were able to follow and use the keys after instruction. Only a few got a term or two mixed up but their classmates and I were able to get them straightened out and all were successful. When I do this lesson/activity again I will have the students do a graph of the number of species they saw and/or make a map showing where the species were located. This would have added some math and social studies into lesson.