Study: Walden Pond’s leaf-out times earlier than in Thoreau’s day

primack-thoreau1Concord Journal
Richard Primack, College of Arts & Sciences

Climate-change studies by Boston University biologists show leaf-out times of trees and shrubs at Walden Pond are an average of 18 days earlier than when Henry David Thoreau made his observations there in the 1850s…

Expert quote:

“By comparing historical observations with current experiments, we see that climate change is creating a whole new risk for the native plants in Concord. Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost.  But if plants wait to leaf out until after all chance of frost is lost, they may lose their competitive advantage.”

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