UC Irvine’s redwoods sit like forlorn Christmas trees near the campus power plant and the Crawford Hall parking lot. They’re miniatures of Northern California’s ancient giants, a dwarf grove with drooping branches. But they’re still standing.
The trees began life with fanfare three decades ago. They are test-tube babies – samples of the world’s first artificially cloned Sequoia sempervirens created by now-deceased UCI biologist Ernest Ball. Manufactured from the straightest, mightiest redwoods, the seedlings enthralled the lumber industry and media alike in their early years.
“These are supertrees,” declared The Christian Science Monitor in 1982. Ball’s work “will revolutionize the lumbering industry,” said a Simpson Timber Co. research manager.
But human projects that tinker with nature don’t always flourish as planned. The original 300 suffered after gophers chewed through underground irrigation. An aboveground system was installed in 1993, and the remaining 75 trees bounced back … at first.
“Some will grow to up to 200 feet tall in the next 40 years,” predicted the Los Angeles Times that year.
Today the trees, as well as Ball’s pioneering work, are largely overlooked. UC Berkeley scientists erroneously claimed in 2007 that they had artificially cloned a redwood for the first time. But in 2008, the UCI copse caught the attention of Diane Pataki, an associate professor of Earth system science and a postdoctoral researcher Heather McCarthy, who assigned Earth system science student Elizaveta Litvak to study them.
A Moscow native who grew up at the city’s edge among birch, oak and pine, Litvak was thrilled to learn of the campus redwoods. “I said, ‘No way – it’s impossible,’” she recalls. “These are such unique trees right here, and nobody knows.”
She earned her doctorate exploring how irrigated trees in semiarid urban areas fare under these unusual circumstances: dry air with plenty of water coming to their roots.
Litvak says the work is not just academic but critical for proper future allocation of fast-disappearing water resources in the often parched Southwest, where – thanks to climate change – greater droughts are predicted. More than 80 percent of the U.S. population lives in developed areas, and tree canopies cover 35 percent of that land, while grass covers nearly half. A third of all water used in metropolitan Southern California is for landscaping. The leafy glades give residents respite from scorching sun and urban heat, but need to be able to survive.
For the redwoods, that seems to be a challenge. On a fall day, Litvak walks through the grove, stopping to examine the undersides of branches and sections of trunk. “These trees are not doing so well,” she says. “Look – the branches are very sparse at the top, and they’re much too small.”
Towering over them are eucalypti, Australian transplants that have succeeded wildly in Southern California. But not the sequoias – they’re suffering from leaf chlorosis, or yellowing, and senescence, premature aging with dead or dying branches. The question for Litvak, who did not at first realize the trees had been cloned from champions, is why they’re faltering here and at other Greater Los Angeles locations.
Everyone knows that redwoods need moisture to grow well. Southern California has a semiarid climate, so perhaps the trees were thirsty, Litvak hypothesized at one point. Yet they seemed well watered – a contradiction that defines life for many ornamental plants in the region.
Litvak hand-built tiny sensors encased in hypodermic needles to continuously measure sap flow with no damage to the trees. The results were surprising. Redwoods actually require less water than most area trees – both native and imported – and far less than turfgrass. California sycamore, London plane, crape myrtle, golden rain and Canary Island pine trees and residential lawns all guzzle more.
So why are the redwoods doing so poorly? Careful analysis of the same data yielded intriguing clues. The stomata – microscopic “mouths” in the trees’ needles – can open wide to gobble up carbon dioxide. But they partially close when exposed to dry conditions. The redwoods aren’t thirsty, but Litvak now theorizes that they may be starving because they’re not able to “eat” enough nutritious carbon. More research is needed.
Litvak says deciphering the riddle is important for soaring stands up north as well as UCI’s little patch. Climate change is predicted to bring warmer temperatures and less cool fog in that region, meaning it could come to mimic Southern California over time.
Despite their woebegone condition, Litvak says, Ball’s redwoods are a treasure. A few days after defending her dissertation, she takes a stroll. The trees look even worse. Then Litvak spies bright-green sprouts curling out of a reddish trunk.
“These are new, natural clones of this tree! If it dies, they could grow,” she says excitedly. “But the parent trees haven’t given up yet. Redwoods measure time in millennia, so the species must be able to endure hardship. They’re amazing.”