Jim Gilbert Leaf-Out Home Page Today's News Spring's Journey North Report Your Sightings Teacher's Manual Search Journey North return to: A/CPB

Background When do the leaves emerge in your region? Let us know! Maps courtesy of: Macalester College Geography Department, and students Uriah McKinney and Debbie Bojar Sugar Maple Please report to Journey North when leaves on trees of any of these 4 species emerge. Our definition of "leaf-out"? Flowering Dogwood Redbud When leaves are the size of a quarter. Quaking Aspen To expand the study, students can investigate the relationship between leaf-out and temperature, just as is done for tulip growth (See "Spring Fever" lesson.) They can measure temperatures locally and can link with other classrooms to compare results. Students will be introduced to the wealth of information about climate on the Internet and investigate how it relates to leaf-out across the continent. A host of activities are planned in hopes that students will ask questions about such things as: How do trees know when it's spring? What happens if the leaves come out too early? How is maple syrup sap related to leaf-out? How do the leaves in my backyard fit into the food chain? Is it true that some songbirds arrive from the Tropics just as the leaves emerge on my trees? Perhaps there's a student who will take the lead and track North America's leaves full course, until they fall back to the Earth next autumn.