What would it be like to spend an entire year embedded in the forest, learning about the human and natural history of a 100-year-old tree?

Local author and Seattle Times reporter Lynda V. Mapes did just that during her Bullard Fellowship in Forest Research, in which she spent 2014-15 at Harvard Forest in Petersham, Massachusetts, learning from scientists, researchers—and an old red oak tree. Her forthcoming book, “Witness Tree,” will bring the climate change story to readers as told through a single tree.

Mapes will show slides from her year in the forest and read from her book, under contract with Bloomsbury Publishing, in this year’s School of Environmental and Forest Sciences annual Sustaining Our World Lecture, 6 to 7 p.m. Thursday, April 21 in Johnson Hall, Room 102. The event is free and open to the public, but organizers ask attendees to preregister online.