By Chris Constantine, California Diver

At 6,300 feet in elevation, Fallen Leaf Lake was carved out of granite by two massive glaciers that traveled northward down the Glen Alpine Valley, leaving behind a lake that is now 3 miles long, just under a mile wide, and 410 feet deep at its deepest point.

Protected from runoff and commercial development, its clear, cold water is home to dozens of ancient trees, many still standing upright. There are 96 trees found so far, standing up to 77 feet tall, with some fallen trees measuring over 100 feet in length. Carbon dating tests have shown that some of these trees lived between the 9th and 12th centuries, and at least three older trees have been dated to between 18 and 35 centuries ago. Like nearby Lake Tahoe, much of the deep lake bed still remains unseen by any humans.

In 1997, some researchers who studied the trees came to the conclusion that the submerged ancient mature conifer trees grew during a medieval megadrought that lasted 150-200 years. Once the drought was over, the lake level quickly rose 150-200 feet, they theorized, quickly submerged the trees and preserved them in the frigid water that hovers just above freezing.

That theory doesn’t seem right according to some, including Tom Loomis, a third-generation resident and avid outdoorsman. Based on evidence seen in the local terrain and found underwater during hundreds of dives on the ancient trees, he believes there’s a completely different answer. Loomis is out to prove what he believes really happened, with the help of citizen scientists and the Undersea Voyager Project, a nonprofit organization located in Napa.

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