'Epidemiological' study demonstrates climate change effects on forests

April 4, 2011
A panorama shows a part of the 27,000 or more trees studied for climate change effects. Credit: James Clark

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 , 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 .

The findings may help scientists and 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.

To conduct the study, Clark and colleagues measured and recorded the growth, mortality and fecundity of each of the 27,000 trees at least once every three years, ultimately compiling an archive of more than 280,000 tree-years of data.

Using a specially designed bioinformatic analysis, they quantified the effects of climate change on over time.

"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 , 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.

"As climate continues to change, we know forests will respond," says Clark.

"The problem is, the models scientists have used to predict forest responses focus almost solely on spatial variation in tree species abundance--their distribution and density over geographic range."

If all trees of a species grew in the same conditions--the same light, moisture, soil and competition for resources--this generalized, species-wide spatial analysis might suffice, Clark says.

Then scientists wouldn't need to worry about demographic variables and risk factors when trying to predict biodiversity losses due to climate change.

"But in the real world, we do," Clark says. "That's where the new concept of climate and resource tracking of demographic rates comes in.

"Trees are much more sensitive to climate variation than can be interpreted from regional climate averages."

The trees studied included 40 species, located in eleven different forest stands in three geographic regions of the Southeast--the southern Appalachians, the Piedmont and the coastal plain.

They were subjected to both natural and experimental variations.

"By quantifying the effects and relative importance of competition [between species] and climate variables," says Clark, "including impacts on fecundity, over both time and space, the model we've developed addresses this need and can be used to guide planning."

Explore further: Forest Tree Species Diversity Depends on Individual Variation

Related Stories

Climate change predicted to drive trees northward

December 3, 2007

The most extensive and detailed study to date of 130 North American tree species concludes that expected climate change this century could shift their ranges northward by hundreds of kilometers and shrink the ranges by more ...

Climate change threatens many tree species: researchers

January 24, 2011

Global warming is already affecting the earth in a variety of ways that demand our attention. Now, research carried out at the Hebrew University of Jerusalem indicates that many tree species might become extinct due to climate ...

Recommended for you

Good fighters are bad runners

July 21, 2017

For mice and men, a strength in one area of Darwinian fitness may mean a deficiency in another. A look at Olympic athletes shows that a wrestler is built much differently than a marathoner. It's long been supposed that strength ...

Genome study offers clues about history of big cats

July 21, 2017

(Phys.org)—A large international team of researchers has conducted a genetic analysis and comparison of the world's biggest cats to learn more about their history. In their paper published on the open source site Science ...

Researchers discover mice speak similarly to humans

July 21, 2017

Grasshopper mice (genus Onychomys), rodents known for their remarkably loud call, produce audible vocalizations in the same way that humans speak and wolves howl, according to new research published in Proceedings of the ...

Researchers discover biological hydraulic system in tuna fins

July 20, 2017

Cutting through the ocean like a jet through the sky, giant bluefin tuna are built for performance, endurance and speed. Just as the fastest planes have carefully positioned wings and tail flaps to ensure precision maneuverability ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.