Research and Application News
For forests, an earlier spring than ever
05 June 2014
Every spring, as the weather warms, trees in forests up and down the east coast explode in a bright green display of life as leaves fill their branches, and every fall, those same leaves provide one of nature's great colour displays of vivid yellow, orange and red.
Over the last two decades, spurred by higher temperatures caused by climate change, Harvard scientists say, forests throughout the Eastern U.S. have experienced earlier springs and later autumns than ever before.
Using a combination of satellite imagery, tower-mounted instruments and on-the-ground observations, research associate Trevor Keenan and Andrew Richardson, associate professor of Organismic and Evolutionary Biology, along with colleagues from 7 different institutions, found that forests throughout the eastern US are showing signs of spring growth earlier than ever, and the growing season in some areas extends further into the fall. That expanded growing season, they say, has enabled forests to store as much as 26 million metric tons more CO2 than before. The study is described in a 1 June paper published in Nature Climate Change.
"What we find in this paper is an increase in the growing season of forests in the eastern U.S. due to recent climate change," Keenan said. "This has been beneficial for forests in the past, but we do not expect the response to continue unchecked in the future. It must also be kept in mind that this positive effect of warming is but one amid a barrage of detrimental impacts of climate change on the Earth's ecosystems."
Image credit: Harvard University - Forest studies