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Observe Budburst and Measure Leaf Growth This Spring
Jan 13, 2026
The North American GLOBE community is encouraged to collect Green-Up data between February and June — whenever plant buds are changing from dormant to fully grown leaves in your location!
Participating is easy. Follow the steps on the North American Phenology Campaign webpage to get started. You may also want to watch the short protocol tutorials for selecting a site and tree to monitor and observing your tree in the spring.
There are many resources available to guide you and help you explore the changing seasons while leaves grow.
- Download and print a GLOBE Phenology Ruler (pdf) with a ruler on one side (to measure Green-Up in spring) and the GLOBE Plant Color Guide on the other (for Green-Down observations in fall). Each PDF prints three rulers.
- Use the Winter Tree Identification Key (pdf) from the University of Wisconsin-Stevens Point to determine your tree species.
- A fun phenomenon for young researchers (or the young at heart!) is the Leaf Budding Timelapses playlist from The Woodland Trust (based in the United Kingdom), including timelapse videos of leaves emerging for 10 tree species.
- Learn about the vernal window with a recorded webinar and related activities and resources from Dr. Elizabeth Burakowski, Research Assistant Professor at the University of New Hampshire. The vernal window is the transition from winter to spring and can be calculated as the number of days between when snowpack disappears and the forest canopy closes (leaves emerge).