Climate change is reshaping forests differently across the United States, according to a new analysis of U.S. Forest Service data. With rising temperatures, escalating droughts, wildfires and disease outbreaks taking a toll on trees, researchers warn that forests across the American West are bearing the brunt of the consequences.

The study reveals a pronounced regional imbalance in forest productivity, a key barometer of forest health that gauges tree growth and biomass accumulation. Over the past two decades, forests in the western United States, grappling with more severe climate change impacts, have exhibited a notable slowdown in productivity, while forests in the Eastern U.S., experiencing milder climate effects, have seen slightly accelerated growth.

Understanding changes in forest productivity in a rapidly changing global environment is a challenging task, says study co-author Kai Zhu, an ecologist at the Institute for Global Change Biology, based at the University of Michigan School for Environment and Sustainability.

“This difficulty arises due to the abundance and interaction of various global change factors,” said Zhu, who helped to frame the study’s research question and provided computer code from a previous study of forest growth.

“Predicting forest productivity becomes even more daunting, yet critical, because it determines their ability to absorb carbon dioxide from the atmosphere. Our research aims to address this challenge with rigorous design and comprehensive analysis to shed new light on this crucial subject.”

The study was published online the week of Jan. 15 in the journal Proceedings of the National Academy of Sciences.

Study: Climate change determines the sign of productivity trends on US forests

Read the full press release on Michigan News.