In eastern Tibetan forest, signs of tree growth amid climate change

Researchers follow a lead from nomadic herders and find a forest getting nutrients and water from thawing permafrost

Date:

September 7, 2016

Source:

University of Oregon

Summary:

Word of mouth from nomadic herders led Lucas Silva into Tibetan forests and grasslands. What his team found was startling: rapid forest growth in tune with what scientists had been expecting from climatic changes triggered by rising levels of carbon dioxide.

On the eastern Tibetan Plateau — in an area where it was thought that “climatically induced ecological thresholds had not yet been crossed” — Silva’s team found that the increasing availability of soil nutrients and water from thawing permafrost is stimulating the chemistry of the wood in a species of fir trees (Abies faxoniana).

“Our results confirmed the reports of local herders and showed a recent increase in tree growth that has been unprecedented since the year 1760,” Silva said. “These result demonstrate that under a specific set of conditions, forests can respond positively to human-induced changes in climate.”

The findings were published Aug. 31 in Science Advances, an online, open-access publication of the American Association for the Advancement of Science.

Nomads had reported their observations to study co-author Geng Sun of China’s Chengdu Institute of Biology in Sichuan, China. The research team traveled to the region in eastern Tibet where they found old-growth forests, smaller patches of trees and trees isolated on the perimeter of the forests.

“We wanted to take a long term view of changes in tree growth across this gradient,” Silva said. “To do so, we combined tree-ring measurements with laboratory analyses to look for changes in growth as well as chemical signals of climatic change.”