In the summer of 2013, Richard Thomas’ study was published in the Proceedings of the National Academy of Sciences and he made national news for conclusions showing that the controversial U.S. Clean Air Act was indeed improving the health of Red Cedar trees in Central Appalachia.
Now, he is expanding the research with a similar study on additional tree species in temperate deciduous forest, including maple, oak, spruce and hemlock trees in similar regions of the United States and China, with the help of a $650,000 grant from the National Science Foundation.
“Our paper that we published in PNAS showed that evidence from one species of tree in one location in West Virginia is recovering from long term—decades of acid pollution,” Thomas said.
“We can’t make a lot of grand conclusions from just one tree species.”
Using the carbon isotope ratios of 13C and 12C that were found in the wood of tree rings, Thomas and his team were able to explore the physiological functioning of the trees over the past 100 years in the original study.
The isotope ratios provided evidence that the stomata, the tiny pores in the leaves that regulate the gas exchange of carbon dioxide and water, were slowly closing over decades of acidic pollution.
There was a change in the isotope ratio around 1982 that indicates that the stomata began to reopen around that time.
Air pollution that negatively impacts forest and aquatic ecosystems, as well as human health, has declined in the United States following the Clean Air Act and subsequent amendments.
“China has been going through the reverse. Instead of reducing their air pollution, air pollution in China has been skyrocketing and getting to really high levels,” Thomas said.
“We want to compare trees that have been going through these different histories of pollution—the east coast of the United States vs. the east coast of China, and see how the trees have been responding to changes in pollution.”
Thomas is collaborating with Bill Peterjohn, associate professor of biology; Amy Hessl and Brenden McNeil in the department of Geology and Geography; Jingxin Wang, Professor of Wood Science & Technology at WVU and a number of collaborators from the Chinese Academy of Forestry in Beijing.
For more information, contact Richard Thomas, at 304.293.6673 or email@example.com.
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