News of the Arroyo

Title:	The 400-year-old Oak tree Caltech was built around is now dead, but there is much to learn from it
Subtitle:
Date:	2017-03-18
Summary:	<b>March 18, 2017</b> - A spectacular 400-year-old Engelmann oak on the Caltech campus has died but leaves many lessons.
Author:	Jason Henry
Publication:	San Gabriel Valley Tribune
Content:	A 400-year-old Engelmann oak tree on Caltech’s campus, growing before Spain colonized California, is now dead. The drought, windstorms and a fungus in the soil led to the ancient tree’s demise, according to California Institute of Technology officials. Engelmann oaks have an average lifespan of about 350 years. “The main cause of death was the Armillaria oak root fungus,” said John Onderdonk, director of sustainability programs at Caltech in Pasadena. Caltech built its campus around the Engelmann oak in 1910. The oak, outside of Parsons-Gates Hall of Administration, offered shade to generations of the brightest minds. The institute discovered the fungus in 2003 and began regularly using fungicides on the tree’s roots. Over the years, drought and windstorms weakened the Engelmann and damaged its canopy. In 2016, heavy rains followed by heat gave the fungus an opportunity to grow. That year, arborists injected 23 fungicides after widespread necrosis was found in the tree’s bark and roots, but the efforts failed. “It’s a progression of these various illnesses, environmental stressors and just age,” Onderdonk said Abraham Lincoln granted the Rancho San Pasqual, where the tree sits, to its owner in 1863. The land was later deeded to Caltech in 1922, according to a plaque near the tree. Caltech’s first building, Throop Hall, went up next to the tree. The second was built across from it. This Engelmann Oak tree on the Caltech campus is estimated to be more than 400 years old and has been standing here before the land was discovered and claimed by Spain. In 1863 this portion of the San Gabriel Valley known as the Rancho San Pasqual was granted to the owner by Abraham Lincoln. This segment of the Rancho that was to become the California Institute of Technology campus was deeded to the institute in 1922.(Photo by Walt Mancini/Pasadena Star-News/SCNG) Engelmann oaks were once common in the Los Angeles region and in Pasadena, where it was sometimes called the “Pasadena oak,” according to Tim Brick, director of the Arroyo Seco Foundation. The tree is now considered “threatened.” Engelmanns have a broad and open canopy with a light green, almost blue, color to the leaves, Brick said. “The one at Caltech was just very special and probably one of the very oldest in the region,” he said. Brick estimates about 400 Engelmann oaks exist today in Pasadena, particularly in the Oak Knoll neighborhood south of Caltech’s campus. Others can be found in the foothills of Arcadia and Sierra Madre. WHAT WILL HAPPEN TO THE TREE NOW? Caltech’s Engelmann, with its remaining branches now held up by supports, was declared dead in February. But the tree’s legacy will continue long after it’s removed — Caltech was able to extract two saplings from the tree and is currently looking for a place to plant them. Arborists will carefully remove and dissect the tree in June, following commencement, and the tree’s wood is expected to provide a scientific window into California’s climate over the past 400 years. “Our researchers in the division of Geology and Planetary Science will look at that from a paleoclimatic perspective,” Onderdonk said. “They’ll look at the tree rings to see what the climate was like and use other techniques to see the environment the tree grew up in over the 400-year time frame.” If possible, some of the wood may be dried and cured to use for commemorative wood carvings and possibly even furniture. One possible idea includes displaying the tree’s ring in connection to scientific accomplishments over the past 400 years. “It was essentially a seedling about the time Galileo made some of his foremost astrophysical discoveries,” Onderdonk said. The tree died in the same year Caltech’s LIGO — which stands for the Laster Interferometer Gravitational-Wave Observatory — detected gravitational waves for the first time. The discovery confirmed predictions by Albert Einstein, who briefly taught at Caltech, about the existence of gravitation waves in his theory of relativity. Onderdonk called it a worthy moment to cap off the life of the university’s longest resident. “It is really cool to think about the tree sort of being bookended by these two significant astrophysical moments in history.” This Engelmann Oak tree on the Caltech campus is estimated to be more than 400 years old and has been standing here before the land was discovered and claimed by Spain. In 1863 this portion of the San Gabriel Valley known as the Rancho San Pasqual was granted to the owner by Abraham Lincoln. This segment of the Rancho that was to become the California Institute of Technology campus was deeded to the institute in 1922.(Photo by Walt Mancini/Pasadena Star-News/SCNG)
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Arroyo Seco Foundation, PO Box 91622, Pasadena, CA 91109-1622 (323) 405-7326 info@arroyoseco.org