Dormancy of Trees

In the fall every year in Iowa there is a pattern of the leaves turning colors and ultimately falling off of trees. This happens as trees enter a seasonal period of dormancy, which allows the tree to preserve energy during the winter. In a process similar to hibernation, the tree’s metabolism and energy consumption slows down. This internal process supports survival of the tree.

How do trees survive the winter?

• Why do you think leaves change colors?
• What do you think makes leaves fall off of trees?
• Why do you think some trees turn colors sooner than others?
• What do you think happens to trees during the winter?

Students could:

• Go outside and find different colored leaves to compare and observe.
• Find different types of leaves and find which tree they belong to based on observations.  
• Go outside and pick leaves that they like and put the leaves under a piece of paper. They will rub crayons on the paper to get the details of the leaves and see the chlorophyll from the leaves.
• Go outside and compare how the trees are now to pictures of how they were during the spring or summer months. They can talk about the main differences between the trees from different seasons. 

• Why Do Leaves Change Color in the Fall?: This link has a lesson that goes through why leaves change colors and why they stay the same during the spring and the summer. There is also an activity/experiment that you can go through with the students. 
• How Do Trees Survive Winter? The Science of Dormancy: This link goes into dormancy and why it’s important.