‘Epidemiological’ study demonstrates climate change effects on forests

National Science Foundation: An 18-year study of 27,000 individual trees by National Science Foundation (NSF)-funded scientists finds that tree growth and fecundity--the ability to produce viable seeds--are more sensitive to climate change than previously thought. The results, published tomorrow in the journal Global Change Biology, identify earlier spring warming as one of several factors that affect tree reproduction and growth.

They also show summer drought as an important but overlooked risk factor for tree survival, and that species in four types of trees--pine, elm, beech, and magnolia--are especially vulnerable to climate change. The findings may help scientists and policymakers better predict which species are vulnerable to climate change and why.

"In a sense, what we've done is an epidemiological study on trees to better understand how and why certain species, or demographics, are sensitive to variation and in what ways," says James Clark of Duke University, lead author of the paper.

…"This work demonstrates the limitations of current modeling approaches to predict which species are vulnerable to climate change and illustrates the importance of incorporating ecological factors such as species competition," says Alan Tessier, program director in NSF's Division of Environmental Biology, which funded the research.

The approach allowed the scientists to calculate the relative importance of various factors, alone and in combination, including the effects of localized variables such as competition with other trees for light, or the impact of summer drought….

Tree rings A felled evergreen in the churchyard of St. Paul's, Tupsley reveals its age. Shot by Pauline Eccles, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license