Beyond the burn: Harvesting dead wood to reduce wildfires and store carbon
Study explores role of dead wood harvesting in wildfire management and carbon sequestration in western US
Florida Atlantic University
image:
A field plot in the Sierra Nevada where researchers surveyed the effects of wildfires.
view moreCredit: Asha Paudel, Ph.D., Florida Atlantic University
A century of fire suppression, combined with global warming and drought, has led to increasingly destructive wildfires in the Western United States. Forest managers use tools like prescribed burns, thinning, mastication, and piling and burning to reduce fuel – live and dead trees, needles and leaves, and downed branches – that can feed intense wildfires. These methods aim to lower fuel levels, reduce crown density, and protect fire-resistant trees, fostering healthier, more resilient forests.
However, prescribed burning efforts haven’t kept up with the rapid buildup of surface fuel, creating a “fire deficit” – the gap between the amount of fuel that has accumulated, and the fire management efforts needed to reduce it – and raises the risk of severe wildfires.
Prescribed fires in the Western U.S. are an essential tool for managing forests and reducing wildfire risks, but they also come with significant social and environmental consequences. These controlled burns can escape and become wildfires, degrade air quality, reduce visibility and pose serious health risks, particularly respiratory illnesses. In the Pacific Northwest, emissions from prescribed fires have been linked to hundreds of deaths, thousands of respiratory problems, and significant workday losses due to poor air quality.
In addition, human activities like deforestation and logging, as well as pests, drought and large high-severity wildfires, diminish forests’ ability to absorb and store carbon, which is essential for reducing CO2 levels in the atmosphere. Effective wildfire management is key to reducing risks, lowering carbon emissions, and enhancing carbon storage to combat global warming.
For thousands of years, Indigenous Peoples in the Western U.S. played a vital role in forest and fire management, shaping ecosystems through practices like controlled low-severity burns and the collection of non-timber forest products for firewood, shelter, cultural items and tools. These traditions inform modern forest management techniques, (e.g., prescribed burning and piling and burning), but the physical harvesting of dead wood without combustion is now being explored as a way to both reduce wildfire risks and carbon emissions.
Researchers from Florida Atlantic University investigated how removing dead wood could reduce wildfire risks and enhance carbon storage in the Sierra Nevada. The study focused on the effects of physical harvesting – removing specific sizes of dead and downed branches and trees – on wildfire behavior and carbon emissions. Researchers also examined which forest management strategies, particularly those involving combinations of fuel treatments, are most effective in reducing wildfire risks, enhancing carbon storage, and promoting long-term forest resilience.
The team simulated the effects of eight different forest management treatments to see how they affect wildfire risks. Along with a “control” scenario that only included wildfire, the treatments included thinning, physical removal of surface fuel, and prescribed burning, either alone or in combination.
The study, published in the Journal of Environmental Management, found that combining physical harvesting with thinning significantly reduced risks like tree mortality and crown fires, while lowering carbon emissions and offering carbon sequestration through products like biochar, charcoal created by heating organic material in a low-oxygen environment, used to store carbon and improve soil.
“In our increasingly warming world with frequent dangerous fire weather, more people and structures at risk in the wildland-urban interface, health risks from exposure to smoke, and need to enhance carbon sequestration to mitigate global warming, scientists need to examine effective alternative management actions,” said Scott H. Markwith, Ph.D., co-author and a professor in the Department of Geosciences, within FAU’s Charles E. Schmidt College of Science. “By combining physical harvesting with thinning – removing smaller or fire-vulnerable trees – evidence from this research suggests we can help restore healthy, resilient forests. This approach, paired with transforming wood into carbon-storing products rather than burning it, could reduce wildfire severity and smoke and carbon emissions, while also generating carbon credits.”
Findings from the study offer important insights for forest management strategies that reduce wildfire risks, lower carbon emissions and boost forest carbon storage.
“Over time, repeated fuel reduction treatments, such as prescribed burns, can emit more carbon than a single wildfire in an untreated forest,” said Rabindra Parajuli, Ph.D., lead author and doctoral graduate from the FAU Department of Geosciences under Markwith’s supervision, and a postdoctoral researcher at the University of Georgia. “However, by harvesting dead wood and converting it into biochar – a stable form of carbon – emissions can be reduced. This process not only mitigates health impacts but also increases carbon sequestration, helping to offset the effects of climate change while promoting healthier forest ecosystems.”
Long-term research, including simulation modeling and field experiments, will play a crucial role in evaluating the effectiveness of this approach over time, with repeated treatments and across various forest types. This research will be especially valuable in exploring its potential for restoring historic wildfire regimes, contributing to the health and resilience of forests in the Western U.S.
Asha Paudel, Ph.D., a doctoral graduate from the FAU Department of Geosciences, was the third study co-author and also a former advisee of Markwith.
- FAU -
About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, Florida Atlantic serves more than 30,000 undergraduate and graduate students across six campuses located along the Southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, Florida Atlantic embodies an innovative model where traditional achievement gaps vanish. Florida Atlantic is designated as a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report, and holds the designation of “R1: Very High Research Spending and Doctorate Production” by the Carnegie Classification of Institutions of Higher Education. Florida Atlantic shares this status with less than 5% of the nearly 4,000 universities in the United States. For more information, visit www.fau.edu.
Asha Paudel, Ph.D., (right) uses the rangefinder/hypsometer to survey fields in the Sierra Nevada.
Researchers surveying fields in the Sierra Nevada.
Researchers surveying fields in the Sierra Nevada.
Credit
Florida Atlantic University
Florida Atlantic University
Journal
Journal of Environmental Management
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Integrating the physical harvesting of dead wood into fuel treatments to reduce wildfire hazards and enhance carbon benefits
Article Publication Date
28-Feb-2025
When life re-emerges after fires: how Mediterranean vegetation regenerates after burning
image:
Image of the research team
view moreCredit: University of Córdoba
Fire is an element that has always been present in Mediterranean ecosystems. Thus, once the direct impacts caused by fires have been overcome, to a greater or lesser extent, in the medium or long term, there is a recovery of forest mass, and life re-emerges.
To what extent does this regeneration occur? How long does it take? What effects does it have on the structure and composition of the vegetation? Answering these questions was the aim of a new study carried out by the Forestry Engineering Department at the University of Cordoba, in which the post-fire dynamics of vegetation in an area of the Sierra Morena mountain rage were analyzed in order to better understand the resilience of ecosystems in the face of different fire recurrence and severity scenarios.
According to the study's principal investigator, Macarena Ortega, the work focused on a non-reforested area affected by two overlapping forest fires in the last 30 years. In this way, through photographic interpretations and field inventories, areas that have burned twice (in 1988 and 2016), areas in which fire has struck only once, and, finally, areas not affected by fires (reference or control areas) were analyzed. Looking at the past of these events, analyzing their evolution over time, and making comparisons between all these scenarios is precisely what allowed the research team to draw conclusions about how vegetation recovers over time.
A scientific basis for prescribed burns
One of the study's main conclusions is that recurrent fires of moderate severity reduce the brush that grows under trees without compromising their regeneration. In the words of another of the researchers who participated in the study, Juan Ramón Molina, "this is further evidence of the utility of prescribed burns, which are, ultimately, moderate-intensity fires, as a scrub management strategy to restore ecosystems and prevent forest disasters." In fact, according to the study, those areas featuring dense woodland and undergrowth and that have only suffered moderate-intensity fires, exhibit full recoveries after 30 years (compared to the control area), almost as if the fire had never occurred.
When woods become overgrown with brush
According to the results of the study, the real problem for woodlands arises when fires occur on a severe and recurrent basis. This was the case in Pino Piñonero, in the area studied; exhibiting recovery after the first fire, the regeneration of the area’s trees was completely thwarted when a second fire struck, as, after severe and recurrent fires woodlands tend to give way to systems in which brush almost completely prevails.
"It would be foolish to plan post-fire restoration without understanding how the ecosystem evolves naturally," adds researcher Macarena Ortega. In this way, the work could serve as a guide to forest restoration strategies and their risks.
The study was carried out by the UCO's Forest Fire Laboratory (LABIF) and the academic institution's Forest Engineering Department, in collaboration with researcher Larissa Yocom, attached to the Forest Resources Department at Utah State University (USA).
Journal
Science of The Total Environment
Article Title
Effects of fire recurrence and severity on Mediterranean vegetation dynamics: Implications for structure and composition in southern Spain
