Study: CO2 prolongs trees' growing season

Houghton, Mich -- A U.S.-led international team of scientists theorize increasing amounts of carbon dioxide in the atmosphere are producing a prolonged tree growing season.

While that may delay the annual display of fall color changes, Michigan Technological University Professor David Karnosky and colleagues said the prolonged growing season is good news for forestry industries.

Karnosky and researchers from Illinois, Wisconsin, Belgium, Britain, Estonia and Italy said their findings suggest forests 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.

The scientists collected and analyzed two years of data from forests near Rhinelander, Wis., and Tuscania, Italy. They found forests on both continents remained greener longer as CO2 levels rose, independent of temperature changes. However, the experiments were too brief to indicate how mature forests might be affected over time.

Karnosky said the study's results are another example of an expanding body of scientific evidence that global climate change is affecting the world's forests.

The research is reported in the journal Global Change Biology.

Copyright 2008 by United Press International.