By Bob Weber
A new study suggests drier weather will likely eliminate any advantage for Canada's boreal forest from higher temperatures caused by climate change.
Scientists had predicted that warmer conditions and a higher level of carbon dioxide, which plants breathe in, would promote growth.
And Martin Girardin of the Canadian Forest Service said some parts of the vast band of green that stretches across the northern provinces are expanding.
But his work published in the Proceedings of the National Academy of Sciences has found that enough forest stands are suffering under climate change to cancel out those benefits.
"There are some trends that are pretty obvious," Girardin said in an interview from Quebec City on Monday.
His study measured boreal forest growth over the last 60 years using decades of satellite imagery combined with tree-ring data from thousands of trees at hundreds of sites. Girardin wanted to see how climate change is affecting what is often called one of the largest undisturbed ecosystems left on Earth.
Temperatures at the study sites have already increased by between half a degree and three degrees.