Undergrad gets her hands dirty learning about redwoods

Lilianne de la Espriella
Environmental studies major Lilianne de la Espriella was as comfortable in the stable isotope lab on campus as in the redwood forest, where she gathered soil samples for her investigation of soil-carbon content. (Top photo by Carolyn Lagattuta; others courtesy of Lilianne de la Espriella)
Lilianne de la Espriella in the stable isotope lab
Lilianne de la Espriella in a redwood forest, surrounded by research equipment

For Lilianne de la Espriella, doing independent, hands-on research as an undergraduate meant literally getting her hands dirty.

De la Espriella gathered and analyzed soil samples from redwood forests as part of her investigation of the ecological significance of coastal redwoods, the iconic trees that grow only from Big Sur to southern Oregon.

"People love redwoods—we call them charismatic megaflora. They're like the polar bears of plants," she said. "They give you a sense of awe."

Forests play a critical role in mitigating the effects of climate change; trees absorb carbon dioxide from the atmosphere as they grow, storing the carbon in their wood. Because they are so massive and long-lived, redwoods store significant amounts of carbon in their trunks, leaves, and branches for hundreds of years, or more. They also contribute to the amount of carbon stored in the soil as organic matter. De la Espriella's project looked at soil carbon content in redwood forests across the state.

"I wanted to emphasize the importance of natural spaces," said de la Espriella. "Setting aside wild spaces and respecting nature is so important, but it's hard to make a case for conservation. How do you communicate the importance of wild spaces in a contemporary way? Climate change is exacerbated by deforestation."

De la Espriella took soil samples from 10 different forests located across the redwoods' range, utilizing the UC Santa Cruz Natural Reserves on campus and at Big Creek to practice her sampling methods. By measuring the soil-carbon content, she hoped to identify the habitats in which redwoods sequester the most carbon. Temperature, rainfall, and latitude all influence the rate of decomposition of soil organic matter. De la Espriella was surprised to find that rainfall and latitude had greater impact on soil carbon than did temperature.

"I found lower levels of soil carbon in the rainier, more northern sites," she said, hypothesizing that higher decomposition and mineralization activity reduced the availability of carbon in the soil. She also took some of her samples immediately after major floods, which she suspects may have skewed her results.

"I'd like to repeat the study and take samples in winter, spring, summer, and fall," she said, acknowledging what every scientist comes to learn: Each experiment yields some answers—and more questions.

"What I learned was six months was not as much time as I thought it would be!" she said, adding that her determination to work independently also limited the scope of what she was able to accomplish. "Having more time and more hands would've really helped. 

Getting the most out of college

De la Espriella conducted the experiment to satisfy the Environmental Studies Department's senior exit requirement.

"It was an opportunity to do something on my own that I create," she said, explaining why she chose to do original research.

De la Espriella, who is 26, arrived at UC Santa Cruz as a junior transfer, having taken classes at Cabrillo College and a community college in Florida, where she grew up. She discovered the natural world after high school, but said, "People thought I was weird for liking nature."

The natural beauty of UC Santa Cruz appealed to her, and when she visited the campus, she knew she would no longer be an outcast. "I told myself, 'I'm going to learn from people here,' " recalled de la Espriella.

Environmental Studies Professor Michael Loik, her adviser on the redwoods project, is one of the people she learned from. Her project was quite ambitious, involving hundreds of miles of travel to collect a total of 120 soil samples from 10 different sites: six state parks, two UC natural reserves, and two sites owned by land trusts. De la Espriella reached out to the Sempervirens Fund and the Land Trust of Santa Cruz County to get access to their properties, and she had to secure research permits from California State Parks. She began talking to Loik about the project last fall and started applying for grants in December to cover travel costs, supplies, and lab time; analyzing soil samples in the stable isotope lab on campus cost $11 each.

"We're fortunate that we are able to give out a handful of financial awards for this sort of project," said Loik, who encourages students to do hands-on research. "It's a springboard for graduate school and careers for a lot of our students. They get skills they can use in future careers with the National Park Service, the U.S. Forest Service, or consulting."

De la Espriella, who is graduating this month, has "made great use of these opportunities," Loik said, noting that she has also been proactive about outreach and sharing her experiences on a National Geographic blog.

De la Espriella was first exposed to hands-on research during UC's system-wide field course on California Ecology and Conservation, a rigorous, quarter-long class she took last fall. Students tour the state visiting UC natural reserves in the desert, the Sierra, redwood forests, and elsewhere, conducting short experiments in each spot.

"It was an amazing experience. They really train you," said de la Espriella. "I was learning by doing. It was what everyone says education should be. It was hard to sit in a classroom after that."

De la Espriella's go-for-it approach to her education was evident in her participation as the only undergraduate who presented her research during the campus's recent annual Climate Conference. For the first time, students were invited to share research findings during an informal program that followed the panel discussion. She was the only undergraduate who approached the organizers about participating.

"It was great, because I got training in how to communicate about science," she said. "A lot of undergraduates came up to me wanting to know how I did this. Doing my own research was a big part of making my experience here what I wanted it to be. Having that autonomy was valuable to me. It can be scary, but I think that's where you grow."