World Without US

Forests once deemed resilient are suffering surprising die-offs. To predict the fate of the world’s woods in the face of climate change, researchers need to understand how trees die.

Forest scientists around the globe are alarmed to see droughts, often exacerbated by fire and infestations of bark beetles, cull trees at scales they have never seen before — from massive swaths of American woodland, to dry forests in Australia where roots can reach down some 50 meters (more than 160 feet), to temperate regions and moist tropical forests where such events were long deemed unthinkable. “Even people who are really knowledgeable and who have a lot of experience out in the field were surprised to see how fast these forests were going down the drain,” says Henrik Hartmann, an ecophysiologist at the Julius Kühn Institute Federal Research Centre for Cultivated Plants in Germany and lead author of an overview of forest die-offs in the 2022 Annual Review of Plant Biology.