Submerged Trees Help In Study Of Tahoe Basin

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A researcher at the University of Nevada, Reno is using samples of submerged, ancient trees to study the ecological history of a Sierra Nevada lake in the Tahoe basin.

John Kleppe, chairman of UNR's electrical engineering department, has been studying samples from trees submerged in Fallen Leaf Lake near Lake Tahoe for five years.

Using a remote-operated vehicle with a grabber, a team assembled by Kleppe last fall pulled a chunk of wood from a log 300 feet below the surface.

Carbon dating conducted by the Lawrence Livermore National Laboratory dated it to 300 B.C., Kleppe told the Tahoe Daily Tribune.

Dating the sunken log is part of an ongoing effort by Kleppe and others to map out historic climate changes in the region.

Kleppe's research is being funded by grants from the U.S. Geological Survey and the Desert Research Institute, a nonprofit division of Nevada's higher education system.

Last July, in an effort to identify an unknown organism in the lake, Kleppe hired a scuba diver to collect translucent, jellyfish-like objects. The diver pulled about 20 or so from a tree floating upright just off shore.

But the translucent blobs -- each about the size of a plum - were not identified because they were stored in formaldehyde, which killed them before a specialist in Colorado could get one under a microscope.

Fallen Leaf Lake, at 6,400 feet elevation, is separated from Lake Tahoe by a thin ribbon of land. Kleppe, who lives on the west side of the smaller lake, hopes to collect more samples of the organisms this summer for analysis.

The biggest challenge in studying submerged trees in the lake - or organisms attached to them - is locating the trees and being able to sample them, he said.

A crew he assembled in October failed to find a targeted tree for an entire day. They were able to locate one only after a diver went down and tied a buoy to it.

Using a water crane, they chained the tree and pulled it near to the shore so chunks could be sawed off and studied. The rest was returned to the lake.

That tree dated to 1215.

"The wood is so beautiful," Kleppe said. "It's perfectly preserved. It smells and looks like wood today. And it started growing in the 10th century."

Water acts as a preservative to wood when submerged for hundreds of years. The resin leaches from wood, keeping it from degrading, he said.