Scientists who study forests say they've discovered something disturbing about the way prolonged drought affects trees.
It has to do with the way trees drink. They don't do it the way we do — they suck water up from the ground all the way to their leaves, through a bundle of channels in a part of the trunk called the xylem. The bundles are like blood vessels.
When drought dries out the soil, a tree has to suck harder. And that can actually be dangerous, because sucking harder increases the risk of drawing air bubbles into the tree's plumbing.