Global warming might shrink half of North American tree ranges

December 3rd, 2007 - 3:45 pm ICT by admin  

Washington, Dec 3 (ANI): A new study has indicated that global warming could cause 130 North American trees to shift their ranges northward by hundreds of kilometers and might also result in shrinking them by more than half.
The study, conducted by Daniel W. McKenney of the Canadian Forest Service and his colleagues, is based on an extensive data-gathering effort and thus more comprehensive than studies based on published range maps.
It includes data from Canada as well as from the United States. Observations of where trees are found are used to define the “climate envelope” of each species.
According to the study, it was found out that if trees were assumed to respond to climate change by dispersing their progeny to more favorable locations, ranges of the studied species would move northward by some 700 kilometers and decrease in size by an average of 12 percent, with some increasing while others decreased.
It was also pointed out that if the species were assumed unable to disperse, the average expected range shift was 320 kilometers, and “drastic” range reductions of 58 percent were projected.
As for studies linking global warming with plants, the climate measures studied were chosen to represent two important gradients for plants: heat and moisture.
For this purpose, two climate change scenarios were modeled. One assumed that carbon dioxide emissions would start to decrease during the coming century, the other that they would continue to increase. Each scenario was investigated with three well-known models of global climate, with broadly similar results.
According to the authors, their study investigated only a sample of the 700 or so tree species in North America, and that under climate change, new species might colonize the southern part of the continent from tropical regions. (ANI)

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