'Torture Lab' Kills Trees To Learn How To Save Them
The droughts that have parched big regions of the country are killing forests. In the arid Southwest, the body count is especially high. Besides trying to keep wildfires from burning up these desiccated forests, there's not much anyone can do. In fact, scientists are only now figuring out how drought affects trees.
Park Williams studies trees at the Los Alamos National Laboratory in New Mexico, but not the way most scientists do. "We're interested in trees that die," he says — spefiically, death by heat and drought.
Sure, lack of water kills trees, but which ones die first, how long does it take, how long can they go without water? "That's a part we don't understand very well as ecologists," says Craig Allen, an ecologist with the U.S. Geological Survey. "We don't know what it takes to kill trees."
Which ones survive, and how many, is the subject of research at the Los Alamos lab.
Nate McDowell runs what you might call a "tree torture" lab. It's actually outside in the desert, near the national lab. He's growing a group of pinon and juniper trees, about 15 feet high. Plastic gutters keep rain away from the tree roots, to simulate drought. The trees themselves are growing inside clear plastic chambers — tubes with no tops. Silvery hoses carry heated air into the chambers.
We climb in through a hole in the chamber where you can immediately feel the heat. It's about 7 degrees hotter than the outside, roughly the increase predicted by computer models of climate change over the next 80 years or so.
McDowell is simulating drought and a warmer climate. He measures how the trees respond — there are instruments stuck into and all over the trees. Even wrapped around the stem.
"Every few minutes they measure the diameter of that tree," he explains. The trees look like patients in intensive care — wired up with tubes coming out of the stems. All to see what it takes to kill it. "Everyone knows it gets hot and dry; you know, beetles show up, the trees are dead," McDowell says, "but we don't really understand it."
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Image credit: David Gilkey, NPR