I vaguely remember mentioning recently my love affair with New England. The postcard shots of the streets strewn with autumn leaves make me happy. One day hope I to live there, but according to new research, the northern forests may be losing their autumn coloring earlier.
Published in a recent issue of the journal Global Change Biology, Professor David F. Karnosky of Michigan Technological University, along with colleagues spread across North America and Europe, have provided evidence that the rising levels of carbon dioxide in our atmosphere is directly affecting the delay of “autumnal senescence.”
“Autumnal senescence” is the changing of colors and falling of leaves that takes place every autumn, and provides us with those picturesque images that often showcase places like Vermont.
“Basically, this is a good-news story for our region’s forests,” said Karnosky. “It suggests that they will become a bit more productive due to the extra carbon being taken up in the autumn, along with the increased photosynthesis throughout the growing season.”
Data was collected over a two year period in forests near Rhinelander, Wisconsin, and Tuscania, Italy by Karnosky and colleagues from Illinois, Wisconsin, Belgium, England, Estonia and Italy. Their evidence has shown that the forests on both continents stayed greener longer with the steadily rising levels of CO2. These findings were independent of temperature changes and length of day.
Granted, this study is too short to be of any long term value, and further research will have to be conducted to evaluate the risk to forests over the long term. Karnosky’s research in Wisconsin however suggests that factors such as increasing ozone levels close to the ground may negate the beneficial effects of elevated carbon dioxide.
Of late there has been a large body of evidence presented that shows global climate change as a real risk to the world’s forests. Many scientists believed that other factors such as temperature and day length were the primary elements halting autumnal senescence. This is the first time though that the independence of carbon dioxide levels has been connected to such symptoms as a halting of the autumn process.
Michigan Technological University via PhysOrg – Forests could benefit when fall color comes late
Photo Courtesy of redjar via Flickr