Droughts Could Be Even Worse for Trees Than We Thought
And the effects can last for years, study says
By Michael Harthorne,  Newser Staff
Posted Dec 16, 2015 6:03 PM CST
A study shows droughts can continue to stunt trees' growths for years afterward, creating a feedback loop of more droughts and dead trees.   (Jake Bacon/Arizona Daily Sun via AP)

(Newser) – The ability of Earth's forests to stand up to droughts may be worse than previously believed. The Washington Post reports that many current scientific models assume trees recover immediately following a drought. But Princeton's William Anderegg demonstrated droughts actually have "legacy effects" on trees in a study published earlier this year. According to Live Science, Anderegg explained the problem Monday at the annual American Geophysical Union meeting. Trees have to work harder to suck up water during a drought; that creates air bubbles in the tree's vascular system that can lead to water- and nutrient-blocking embolisms. Anderegg's team found that droughts can continue to affect trees for up to four years after normal conditions return.

During the years following a drought, trees are prevented from growing at their normal rates, possibly hurting the amount of carbon dioxide they pull out of the atmosphere, the Post reports. Even worse, dead trees dump greenhouse gases back into the atmosphere, creating a feedback loop of more droughts and dead trees. While climate models suggest droughts will become more frequent and severe in the coming years, Anderegg tells Live Science it's not too late to prevent the worst of it by reducing carbon emissions. "The future of a lot of these forests really rests in our hands,” he tells the Post. “The sooner and the more effectively we address climate change, the less risks forests will face.” (Listen closely, and you can hear California's drought.)