There's more than one cliff drawing controversy this month. The federal farm bill is one of many items caught in congressional gridlock. The bill resets U.S. agriculture policy every four years, and most farmers are still covered by crop insurance and other programs until next planting season. But there's one exception: dairy.
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.