WASHINGTON, April 4 (UPI) -- Tree growth and fecundity -- the ability to produce viable seeds -- are more sensitive to climate change than previously thought, an 18-year U.S. study found.
The study of 27,000 individual trees by National Science Foundation-funded scientists identified earlier spring warming as one of several factors that affect tree reproduction and growth. It also found summer drought was an important risk factor for tree survival, and species in four types of trees -- pine, elm, beech, and magnolia -- are especially vulnerable to climate change, an NSF release said Monday.
The study will help scientists and policy makers understand which species are vulnerable to climate change and why, the researchers said.
"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," lead study author James Clark of Duke University said.
Clark and colleagues measured and recorded the growth, mortality and fecundity of each of the 27,000 trees at least once every three years and said studying individual trees, not just forests as a whole, is important.
"As climate continues to change, we know forests will respond," Clark said. "Trees are much more sensitive to climate variation than can be interpreted from regional climate averages."