American Trees Are Moving West, and No One Knows Why

As the consequences of climate change strike across the United States, ecologists have a guiding principle about how they think plants will respond. Cold-adapted plants will survive if they move “up”—that is, as they move further north (away from the tropics) and higher in elevation (away from the warm ground).

Autumn colours in the Great Smoky Mountains National Park, near Cherokee in North Carolina. 

A new survey of how tree populations have shifted over the past three decades finds that this effect is already in action. But there’s a twist: Even more than moving poleward, trees are moving west.

About three-quarters of tree species common to eastern American forests—including white oaks, sugar maples, and American hollies—have shifted their population center west since 1980. More than half of the species studied also moved northward during the same period.

These results, among the first to use empirical data to look at how climate change is shaping eastern forests, were published in Science Advances on Wednesday.

Read Robinson Meyer’s story on The Atlantic - “American Trees Are Moving West, and No One Knows Why.”

Drought and climate threatening U.S. forests

Drought and climate change are now threatening almost all the forests of the continental US, according to new research.

Scientists from 14 laboratories and institutions warn in the journal Global Change Biology that climate is changing faster than tree populations can adapt

Existing forests, effectively and literally rooted to the spot, are experiencing conditions hotter and less reliably rainy than those in which they had evolved.

Read the Climate Home story - “US forests struggle as drought and climate change bite.”