Scientists Explore the Foggy Link Between Redwoods, Climate Change

By Lorena Anderson, UC Merced

California’s coastal redwoods are one of the state’s most prominent icons, drawing more than 2 million visitors a year. Another prominent icon? Fog, winding its way across the coast and through the trees. Climate change may be impacting both of them.

Climate change may affect the fog that waters California's iconic coastal redwoods.

Climate change may affect the fog that waters California’s iconic coastal redwoods.

While coastal redwoods typically get plenty of water during the winter, fog helps them get through the summer. But fog is on the decline. What that means for the coastal redwoods in currently unclear.

A new National Science Foundation grant supports a team of researchers from seven institutions — UC Merced, UC Davis, UC Berkeley, UCLA, Stanford University, the Carnegie Institution for Science and Oregon State University — in forming an interdisciplinary “uber-university” to study the relationships between fog, climate change, redwoods and the human response.

The research team plans to analyze differences in fog cover and redwood health between three sites: Big Basin and Landels-Hill Big Creek Reserve in Big Sur, and a site north of Santa Cruz.

Named The Summen Project, after the Native American word for “redwood,” the $1.75 million, three-year study is part of NSF’s Coastal Science, Engineering and Education for Sustainability (SEES) program, a $13 million push to study coasts around the world.

Fog on the decline

“The big problem is that fog is on the decline, and that might be due to climate change and expanding urban heat islands,” said project leader Elliott Campbell, a professor with UC Merced’s School of Engineering.

Interactions between redwoods and the physical environment have received relatively little attention, though, mainly because until recently, models couldn’t simulate the fog that creates the link. That made it difficult for researchers to interpret historical observations or to project climate change impacts on redwoods.

Travis O’Brien, an assistant adjunct professor at UC Davis and a research scientist at Lawrence Berkeley National Laboratory, was able to successfully simulate the processes that drive seasonal changes in fog for the first time as part of his PhD dissertation research. He will be running climate simulations for this project.

“Fog involves a complex interaction between the ocean, the atmosphere, and vegetation on land — all of which are changing in different ways due to increases in greenhouse gases and due to urbanization displacing natural ecosystems,” O’Brien said. “This project aims to provide answers to these questions.”

Fog an obscuring factor

The fog itself can make it difficult to understand how redwoods will respond to changes in fog.

“The trees and how they function are literally enshrouded in fog,” said Mary Whelan, an NSF postdoctoral fellow at UC Merced who is working on the project. “Leaves are covered in tiny openings that let air in and out. Normally, we could measure how much water is escaping the leaves to see how well the tree is ‘breathing.’ But the mist puts a damper on traditional methods.”

It’s important to understand the vulnerabilities of the coastal ecosystems in part because by 2025, an estimated 75 percent of humans will live near coasts. If current population trends continue, crowded U.S. coasts are projected to see populations grow from 123 million people to nearly 134 million by 2020.

Can the redwoods make climate change personal?

While the project will provide information about coastal redwood resilience and establish a foundation for future work, it will also investigate whether learning about climate change impacts to the redwoods can influence people’s perceptions of climate change.

“We believe that, when people learn about climate-related impacts to a species that is particularly iconic — in this case, the coastal redwoods — their perceptions of climate change will become more salient, personal and pressing,” project co-leader Stanford Professor Nicole Ardoin said. “As a result, their interest will be piqued and their climate-related behaviors may be influenced, as well.”

The scientists will host a series of stakeholder meetings with nongovernmental organizations, park employees and land managers to discuss the results.

“California redwoods are not just an iconic part of the state experience — they are a bellwether for the impact of climate change on California,” Secretary of the California Natural Resources Agency John Laird said. “This study will help us understand the changing health of the redwoods and suggest possible steps we can take to protect the health of the trees.”

The Summen Project is under the umbrella of the UC-wide Institute for the Study of Ecological and Evolutionary Climate Impacts Opens a New Window (ISEECI), formed through UC President Janet Napolitano’s Research Catalyst Awards. Led by UC scientists, ISEECI coordinates studies for understanding and potentially mitigating climate impacts. Researchers use the 39-site UC Natural Reserve System as a living laboratory to study the effects of climate change on California ecosystems.

This post was adapted by Kat Kerlin from a post by Lorena Anderson, UC Merced. 

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