This project aims to rescue Oakland’s namesake tree species
As climate change threatens Oakland’s namesake tree, Northeastern has launched a transplant program to safeguard the city’s urban forest.
OAKLAND – The roots extending from Oakland’s namesake oak tree genus run deeper throughout the Bay Area city than its topsoil.
Depictions of the ancient trees adorn road signs, billboards and its official flag, enduring symbols that have united the city’s vibrant tapestry of peoples and cultures since its founding 174 years ago.
Like other oak varieties endemic to California, the coastal live oak (Quercus agrifolia) supports immense biodiversity, a “keystone” species relied upon by mammals, birds, insects, humans and the Earth itself, said Gabriela Garcia, an assistant professor at Northeastern University’s Department of Marine and Environmental Sciences (MES) whose research focuses on agroecosystems.
But some climate models predict the oaks’ natural habitat may shrink by 50% in the next 50 to 100 years, she said. Already, the vast oak forests that once spanned the area have shrunk due to bacterial blight and regional warming.
To establish a climate change-proof future for the trees that gave Oakland its name, campus sustainability manager Andrew Gonzales and a group of Northeastern students have kicked off a novel tree-transplant operation using oak saplings from Southern California.
In trialing the more drought- and heat-resistant species 一 which will also be made available to Northeastern faculty across the global campus network for their own research purposes 一 Gonzales hopes to identify promising replacements for the coastal live oak that can one day diversify Oakland’s urban forest and safeguard its long-term survival.
“Experiments like this are still relatively rare, and it’s great to see this experiment happening on the Oakland campus,” said Katie Lotterhos, whose research at the Lotterhos Lab at Northeastern’s Marine Science Center investigates climate’s effects on biodiversity. “I’m excited to see what they find.”
Gonzales and the students planted four saplings this month in strategic locations on the Oakland campus, with plans to add another 20 to 30 specimens during the coming academic year, he told Northeastern Global News.
Among them are Quercus tomatella 一 a type of oak native to Catalina Island 一 and the silver leaf oak, which comes from northern Mexico, Gonzales said. They will also plant Quercus rugosa, the red netleaf oak, whose leaves have minuscule hairs that can collect dust and other airborne particulates.
“Part of the reason why we’re picking these trees is because they’re drought tolerant … and some have shown a little bit more disease and pest resiliency than the coastal live oak,” Gonzales said.
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Some of the oak saplings, which Northeastern obtained from Devil’s Mountain Nursery, are expected to grow comfortably uphill from the southwest-facing Oakland campus farm, Gonzales said. Others will sit beside the busy Seminary Avenue that flanks the eastern edge of campus, intentionally introducing them to vehicle exhaust and residual heat from the asphalt.
Transplanted saplings are typically measured on a number of factors as they grow accustomed to a new home, including their height, trunk diameter, stress indicators such as leaf drying, and reproduction of flowers and acorns, according to Randall Hughes, an MES professor researching the consequences of biodiversity change.
“These experiments are important to conduct because sometimes there are unexpected trade-offs among those responses when organisms are moved to a new environment, because they are not only having to deal with temperature or drought or disease … but they are having to deal with changes in many of those variables at once,” Hughes said.
Researchers can also look at whether the new oak species’ genetic material mixes with closely related trees on campus, and what the consequences of that genetic mixing will be, Lotterhos said. A successful transplant could help “pre-adapt” existing trees to climate change, but genetic incompatibilities could have the opposite effect, she said.
A greater variety of healthy, well-adapted trees in urban areas fortifies the entire forest’s resilience capacity because it mimics the natural diversity found in non-urban systems, according to Garcia.
“If all the trees are clones of each other or even the same species 一 a monocrop 一 then they’re much more vulnerable to a pest outbreak than it is if you have lots of different genotypes,” Garcia said.
The transplant experiment is a unique opportunity for experiential education, she added, and a fulfillment of Northeastern’s promise to bridge local research with global impact.
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“It’s always the position for universities … to test things out in ways that local city governments maybe don’t have the capacity or funding to do,” Gonzales said as he clipped dry leaves from one of the saplings. “We’re thinking of the public good, of adding to the body of knowledge of humanity.”
Northeastern will be inviting representatives from the city of Oakland to observe the progress of the oak saplings in the years to come, Gonzales said, a proof of concept for widespread planting in the future.
The mighty oak tree’s pivotal role as a keystone species in Oakland is matched only by its cultural importance to the city, further raising the stakes of a successful transplant experiment, Gonzales said. The threat is also personal, he added, as vulnerable coastal live oaks are the most populous tree variety on the verdant, 135-acre Oakland campus, with over 1,500 individual specimens.
“It’s something near and dear to the Oakland community,” he said. “It will be an interesting future in 100 years, let’s say, if maybe only one out of 10 of these oaks are surviving.”
