![]() ![]() Its footage showed the otherworldly trees with their roots supported by rocks and sediment buildup. Whenever he hooked a tree, he marked its location and later sent down a camera mounted on a propeller-driven Remotely Operated Underwater Vehicle, or ROV, with a pincer in the front for grabbing samples, and lights mounted on its side. He rigged a weighted 150-foot line between the undersides of two boats and slowly scoured the lake. ![]() Once Caterino found the first tree, Kleppe began combing the lake for more. I never snagged and never caught anything." Curious, he finally asked Caterino to investigate. "It looked like a fish strike," says Kleppe. For 15 years, his fishing lures bumped against an unknown something in the deeps. John Kleppe, a professor emeritus at the University of Nevada-Reno who owns a lakeside home on Fallen Leaf, accidentally discovered the mysterious climatic archive. Such megadroughts are a frightening prospect, and it's possible they could strike again. Researchers have found stumps of long-dead trees in rivers, lakes and marshes in the region, indicating not one, but two medieval megadroughts - the other lasting about 140 years in the 13th and 14th centuries, dwarfing the 20th century's Dust Bowl. The medieval trees' existence adds to the body of research documenting the Sierra Nevada's past megadroughts. There are also three older trees, which drowned between 18 and 35 centuries ago, standing upright on the lake floor, which suggests that severe droughts struck even further back in time. In the wetter years that followed, the lake quickly refilled, drowning the trees and sealing them in a liquid catacomb, safe from insects and fungi in the deep, low-oxygen water. Fallen Leaf Lake dropped about 150 to 200 feet below its current level, allowing the trees to grow above the lower shoreline. They grew during a 200-year megadrought in the Sierra Nevada between the 9th and 12th centuries, when precipitation in the area fell to less than 60 percent of the average between 19. This botanic relic is one of several medieval trees, ranging from 68 to 100 feet tall, standing upright at the bottom of the lake. Even though the tree it came from had been stewing underwater for 800 years, it still smelled pungently of sap. He surfaced a few minutes later, branch in hand. Having dived some 400 high-altitude lakes over the course of 30 years - often reciting a protective Washoe prayer beforehand - Caterino, director of the Lake Tahoe-based environmental nonprofit Alpengroup, doesn't shy away from occupational hazards. "I'd be at the bottom of the lake, dead in about five minutes," he mused. That autumn day in 1997, Caterino briefly considered what would happen if he accidentally nicked the air hose running to his mouthpiece, or cut his orange dry suit, letting the 39-degree water rush in. Bubbles streamed from the regulator in his mouth, rising through the blue alpine water and green flecks of algae in Fallen Leaf Lake. A curved tree saw in his gloved hand, a scuba tank on his back, Phil Caterino worked quickly to slice through a pine branch 100 feet below the surface of a small tarn south of Lake Tahoe. ![]()
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