Researchers and the public convene to discuss the ecological effects of pile burning at Jasper Ridge Biological Preserve ('Ootchamin 'Ooyakma)

Figure 1. A panel of the broad topics represented at the pile burn research convening.

California’s landscapes evolved with fire, both natural and anthropogenic. For thousands of years, people used fire and gained a deep understanding of the effects of burning on the ecology and natural history of the land. Unfortunately, however, European colonization disrupted this traditional ecological knowledge, eventually causing the ever-worsening catastrophic wildfires we see today. Researchers are now grappling to understand the effects on public health and how to approach burning as a vegetation management strategy in the long term. Findings will be useful and complementary to the effort to revitalize Indigenous science toward sustainable land stewardship.

Stanford researchers leveraged a fuel reduction treatment in the form of burning more than 180 piles in March 2024 at Jasper Ridge Biological Preserve ('Ootchamin 'Ooyakma) to address critical research questions about the use of prescribed fire (Figure 1). On February 18, 2025, almost one year after the pile burning, researchers convened to present progress updates and discuss the future of fire at the preserve and beyond. Researchers then discussed what inspired them from other presentations, the potential for collaboration among teams, and how to best communicate their findings to the broader community.

Pile burning was one of various tools used to remove vegetative fuel along the perimeter of the preserve to create a fuel break that helps mitigate wildfire risk for both the preserve and neighboring properties. Compared to wildfires, vegetative piles often burn at a lower intensity and for a shorter period, and often produce less smoke than a large wildfire. Of the approximate 180 piles burned across 6 acres, about 25% were used for nine research projects, mostly in the chaparral.

The wide range of results across nine projects allowed researchers and the public to think through various scales of time, space, biodiversity, trophic level, and even technology (Figure 2). The talks were grouped into three sessions based on scale and spatial (above/below ground) focus, yet it was clear that all projects were interconnected as they revolved around the drastic changes that fire can bring. 

Summary of research presentations

From the session on microclimate to landscape level effects, we learned that using common air quality sensing methods still poses its challenges in remote areas like accessing Wi-Fi to transfer data, and Stanford students are helping resolve this issue through the development of their own radio sensors led by Dr. Jessica Yu. PhD Candidate, Daniel Neamati, is adapting imaging and modeling technology mostly used in indoor settings to the outdoors, with the goal of translating its applications to track vegetation growth. Through fine resolution climate sensors, Prof. Jeff Dukes detected wider daily fluctuations in air temperature and soil temperature, as well as lower soil moisture, which can affect plant and soil microorganism growth.

Figure 2. Research updates were shared through poster or oral presentations. Clockwise from top left: Bill Gomez, Adriana Hernandez PhD, Sheena Sidhu PhD, Trevor Hebert, Lydia Villa, Prof. Jeff Dukes. Images by preserve staff.

Researchers addressing belowground to aboveground ecological connections found a reduction in plants (see Lydia Villa’s project) and fungi and nematodes (see Dr. Amaury Payelleville’s project), at the center of burn piles. Investigators will continue to monitor the growth of plants and microorganisms to assess changes one year post-burns. Vegetative responses to other fuel reduction treatments like mastication and mowing are also being evaluated. A study by Teso Coker, PhD Candidate, considers changes in the nutrients running off from hilltop soil into streams and Searsville reservoir, and lab experiments are underway.

The third session focused on soil research. PhD Candidate, Adrian Wackett, presented their findings from measuring radioactive isotopes after wildfires in the Sierra Nevada mountains, and they will compare how pile burning changes isotopes in the soils at Jasper Ridge. Preliminarily it seems that wildfires transform chemical isotopes, leaving behind artifacts, which may lead to incorrect interpretations of soil erosion rates. Another team led by Dr. Alandra Lopez compared how chemical properties are influenced by vegetation types, soil types, and fire type. Her team found increases in soil pH immediately after fire and remaining alkaline for months after. High soil pH can negatively influence the availability of nutrients and how nutrients are absorbed by plants, and it can favor certain microorganisms from growing, while inhibiting others. Our final presenter, Katie Huy, found an increase in less degradable forms of carbon, which are stored in the soil longer than other forms of carbon, potentially creating a long-term carbon sink.

During the poster sessions, several projects were presented by undergraduate research interns Kiara Fufunan, Rachel Lit, Nick Rodriguez, and Zander Opperman. You can find a description of each project in the abstract booklet. One project by docent Bill Gomez, investigated the effects of fuel breaks on woodrat nest activity in chaparral, oak woodland, and poison oak thickets. The woodrats abandoned or infrequently visited nests after fuel reduction, then overall activity recovered after 9 months, except at nests in the mastication area where a buffer was not maintained around the nest. The researcher presented a poster, and you can read more about it in this blog.

Faculty panel session

The preserve’s Faculty Director, Prof. Tad Fukami, led a discussion with faculty Prof. Jeff Dukes, Prof. Jane Willenbring, and Prof. Chris Field, to more broadly contextualize pile burning and research (Figure 3). The proliferation of invasive species calls for a hands-on approach to land management, as does increased fire risk due to higher tree density. With the preserve sitting at the wild-urban interface, it’s an opportune location to answer questions about how to set restoration goals, especially if we don’t have historical information to know what we are restoring to and in light of climate change; how can treatments be specific to a landscape while serving as a lesson for other lands; how fire risk and invasives management unfold in the long-term after treatment.

Figure 3. Faculty Director, Tad Fukami, moderates a discussion with faculty who are conducting research in the pile burn areas, Prof. Jeff Dukes, and faculty who advise student researchers, Prof. Chris Field and Prof. Jane Willenbring. Image by preserve staff.

Researchers stayed for an afternoon session to share their takeaways from other presentations, new interpretations of their own work, and responses to the community’s questions. All researchers concurred that the community would benefit from learning the results of their projects through blogs, community events, and working with community organizations in the area.

The future of fire at the preserve

The pile burns brought opportunities for research and awoke an abundant population of a rare plant not seen for decades at the preserve. Yet, new sun exposure and bare soil also provided a chance for invasive species to colonize. Hundreds of stinkwort sprouted in newly treated areas (Dittrichia graveolens) where it had never been seen before and were immediately pulled by staff to prevent an infestation and possible transition to an undesirable ecosystem. With ongoing fuel reduction activities in the short-term and long-term future, JRBP ('O'O) is building a maintenance plan.

In addition to ongoing monitoring, the staff technology specialist, Trevor Hébert, will also continue imaging the burn areas with a drone, to help track vegetation changes as maintenance continues, and to be a long-term resource for other researchers (Figure 4).