Cal Poly Biology Professor and Students Discover Record Tree in Poly Canyon

Eucalyptus Karri Record Tree SAN LUIS OBISPO -- Cal Poly Biology Professor Matt Ritter and three of his students recently discovered what is thought to be the tallest Karri Eucalyptus (Eucalyptus diversicolor) tree in North America.

Ritter, a biology professor and head of the Cal Poly Plant Conservatory, spotted the massive tree in Poly Canyon in 2005. But it wasn’t until late November 2007 that he and graduate students Jenn Yost and Chris Wassenberg, along with undergraduate Justin Bence, were able to climb to the top of the giant tree to measure it.

Using ropes and harnesses, the four researchers were able to get an accurate measurement of the tree’s height by dropping a line to the ground from the upper canopy.

They recorded the tree at a height of 154 feet, a diameter of seven feet, with a
75-foot wide crown.

Measuring the tree Ritter submitted the data to the California Registry of Big Trees, part of a national forestry database. The Poly Canyon Karri Eucalyptus has been accepted as the tallest tree of its type on record -- almost 100 feet taller than the previous North American record holder, a San Clemente tree 59 feet tall.

"In my research on California eucalyptus ecology I've looked for all the specimens of E. diversicolor and other species planted throughout the state, Arizona, Hawaii and
Florida," Ritter added. "This is by far the oldest and largest specimen."

Like other types of eucalyptus trees, the Karri is native to Australia. There, it is found only in the towering forests south of Perth, on the southwestern tip of the continent, and is relatively uncommon in the U.S., according to Ritter.

The record tree, estimated to be between 80 and 100 years old, can be found in the
bottom of Brizzolara Creek in Poly Canyon, the only Karri in a stand of Blue Gums.

Cal Poly is home to two other record holders in the California Big Trees Registry. Both are state and national tall tree recordholders, and both grow on Cal Poly's Swanton Pacific Ranch facility just north of Santa Cruz.

The ranch is home to the largest California Buckeye tree (Aesculus californica), 46 feet tall, and largest Caifornia Nutmeg tree (Torreya californica), 96 feet tall.

For more details or information on big trees,

Visit the Cal Poly Plant Conservatory Web site at:
www.plantconservatory.calpoly.edu

Or visit the California Registry of Big Trees Web site, maintained by Cal Poly, at:
http://www.ufei.org/Bigtrees/index.html.

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