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Tree Identification - Using a Dichotomous Key for Conifers
Trees can be divided into two main groups: Conifers (gymnosperms) and Deciduous (angiosperms)
Conifers have leaves that are green needles. Most keep their green needles all year long, except tamaracks/larch. Conifers have cones, female seed cones, male cones have pollen. At certain times each year, pollen is released and sent by the wind to find the seeds. The seed cones are pollinated producing fertile seeds. When the cones are dropped or harvested by animals, seeds dropped into the soil produce new conifers.
The conifers you might find on your nature trail are: white pine, red pine, balsam fir, spruce, hemlock and tamarack. (There are many more, this is a small sampling...)
Deciduous trees have green leaves. They lose their leaves every autumn and grow them back each spring. Deciduous trees have flowers that are also pollinated by the wind or insects and produce seeds inside a fruit. The fruits falls or is eaten and distributed by an animal. Deciduous tree flowers can look like standard flowers or they can be very different like a catkin as on most forest trees.
Deciduous trees make a variety of fruits (with the seeds inside) i.e. apple trees-apples, maple trees-samaras, oak trees - acorns, birch trees make cone-like fruit called strobile, cottonwood trees make seeds on fuzzy parachutes.
Activity: Make a tree identification chart.
1. Collect samples from the different trees. If you can collect a flower, seed or fruit (cone in conifer) that is even better. Keep each sample separate.
If you want to include the students in the collection process, that is beneficial to them. It helps to see the whole tree and what it looks like. Because this is a small sampling of trees for this activity, collect or locate these trees ahead of time to make the activity successful.
If you collect the samples for them, afterward it helps to have them try and identify these trees in their neighborhood or schoolyard.
For all conifers, use the Conifer Key.
For deciduous trees, use the Deciduous Tree Guide.
3. Life Science Standards
Science subject matter focuses on the science facts, concepts, principles, theories, and models that are important for all students to know, understand, and use.
K-4 Characteristics of Organisms, life cycles of organisms, organisms and environments
5-8 Structure and function in living systems, reproduction and heredity, regulation and behavior, populations and ecosystems, diversity and adaptations of organisms
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