Dr. Keeley is currently a research scientist with the U.S. Geological Survey, stationed at Sequoia National Park.
Prior to this appointment, he served one year in Washington, D.C. as director of the ecology program for the National Science Foundation. He was professor of biology at Occidental College for 20 years and spent a sabbatical year at the University of Cape Town, South Africa. He has more than 350 publications in national and international scientific journals and books. His research has focused on ecological impacts of wildfires as well as other aspects of plant ecology, including rare plants, rare habitats such as vernal pools, and plant physiology. In 1985 he was awarded a Guggenheim Fellowship and is a Fellow of the Ecological Society of America and an Honorary Lifetime Member of the California Botanical Society. He has served on the Los Angeles County Department of Regional Planning Environmental Review Board, and the State of California Natural Communities Conservation Program (NCCP) Board of Scientific Advisors.
Professional Experience
U.S. Geological Survey, Western Ecological Research Center, Research Scientist
(ST Scientist), 2015–present
(GS series 0408), 1998–present
University of California, Los Angeles, Adjunct Full Professor, 2001-present
Rancho Santa Ana Botanic Garden, Research Associate, 1997–present
National Science Foundation, Program Director 1997–1998
Occidental College,
Professor 1988–1998
Department Chair 1982–1988
Assist/Assoc Professor 1977–1988
University of Cape Town, Visiting Professor 1990
Education and Certifications
Ph.D. (Botany) University of Georgia, Athens, 1977
M.S. (Biology) San Diego State University, 1973
B.S. (Biology) San Diego State University, 1971
Honors and Awards
Fellow, Ecological Society of America, 2014
Distinguished MEDECOS Fellow, 2011
USGS Performance Award, 2011
USGS Star Award, 2008
Honorary Lifetime Member, California Botanical Society, 1998
Fellow, Southern California Academy of Sciences, l994
Guggenheim Fellow, l985–l986
Sterling Award for Outstanding Teaching, l985
Science and Products
WERC Fire Science
Understanding Fire-caused Vegetation Type Conversion in Southwestern Conifer Forests under Current and Future Climate Conditions
Preventing Extreme Fire Events by Learning from History: The Effects of Wind, Temperature, and Drought Extremes on Fire Activity
Southern California Wildfire Risk Scenario Project
Invasive Plants and Fire
Environmental Change and Fire
Balancing Fire Hazards and Resource Protection
Sequoia and Kings Canyon Field Station
The Effect of Prolonged Drought on Chaparral Dieback within the Perimeters of the Thomas and Woolsey Fires in Southern California, USA
The Effect of Prolonged Drought on Chaparral Dieback within the Perimeters of the Thomas and Woolsey Fires in Southern California, USA
Data for Use in poscrptR Post-fire Conifer Regeneration Prediction Model
Survey Data for Chaparral Vegetation in Masticated Fuel Treatments on the four Southern California National Forests (2011-2012)
Vegetation type conversion in chaparral in San Diego County, California, USA between 1953 and 2016
Demographic data for Hesperocyparis forbesii on Otay Mountain 2004-2017
Chaparral Type Conversion into Herbaceous Vegetation in Coastal Southern California from 1947 to 2014, Data Compiled from Aerial Imagery, Geographic NAD83 (2017)
Mechanisms of forest resilience
Large California wildfires: 2020 fires in historical context
Ignitions explain more than climate or weather in driving Santa Ana Wind fires
Wildfires and global change
U.S. Geological Survey wildland fire science strategic plan, 2021–26
Multiple-scale relationships between vegetation, the wildland–urban interface, and structure loss to wildfire in California
Contrasting prescription burning and wildfires in California Sierra Nevada national parks and adjacent national forests
Seed production patterns of surviving Sierra Nevada conifers show minimal change following drought
Effects of postfire climate and seed availability on postfire conifer regeneration
Why are so many structures burning in California?
Subspecies differentiation in an enigmatic chaparral shrub species
Protecting the wildland-urban interface in California: Greenbelts vs thinning for wildfire threats to homes
poscrptR
Seed source, not drought, determines patterns of seed production in Sierra Nevada conifers
Science and Products
- Science
WERC Fire Science
WERC scientists are defining the past, present, and future of wildfires for wildlife and human communities. Explore this webpage to learn about specific, ongoing projects across California and parts of Nevada.Understanding Fire-caused Vegetation Type Conversion in Southwestern Conifer Forests under Current and Future Climate Conditions
Fire size, frequency, overall area burned, and severity are increasing across many vegetation types in the southwestern U.S. In many cases, large contiguous areas are burning repeatedly at high severity, triggering vegetation type conversions (VTC), where once-dominant coniferous forests fail to return to their pre-fire state, often transitioning to shrub- or grass-dominated systems. Loss of thesePreventing Extreme Fire Events by Learning from History: The Effects of Wind, Temperature, and Drought Extremes on Fire Activity
The 2017 fire season in California was highly unusual with its late seasonal timing, the areal extent it burned, and its devastation to communities. These fires were associated with extreme winds and were potentially also influenced by unusually dry conditions during several years leading up to the 2017 events. This fire season brought additional attention and emphasized the vital need for managerSouthern California Wildfire Risk Scenario Project
Every year, wildfires devastate the landscapes of Southern California from Los Angeles to San Diego. How has a higher number of human-caused fires affected fire hazards and threats to resources? WERC’s Dr. Jon Keeley and collaborators are analyzing fire patterns across the state to help cities balance their management of fire hazards and natural resources.Invasive Plants and Fire
Fire has had a very different influence on the forests and shrublands of California. Unlike the case in many forests where fires have been excluded for over a century, shrublands throughout the state have experienced the opposite impact. Invasive grasses that burn more readily than native plants have increased the frequency of wildfires in southern California shrublands. As fire clears swathes of...Environmental Change and Fire
The effects of a changing environment can ripple throughout an ecosystem. Increased temperatures and more frequent and severe droughts in the future may influence wildfire patterns as well as water resources for communities. Dr. Jon Keeley and partners are using nearly a century’s worth of fire data to aid local landowners, and state and Federal agencies in planning for wildfire on evolving...Balancing Fire Hazards and Resource Protection
Human impacts on fires across California have been quite diverse. In many forests, fires have been nearly excluded over the past century, causing an unhealthy accumulation of dead vegetation and a greater threat of severe fires. However, on much of California’s lower elevation foothills and valleys, humans have greatly increased fire frequency. These landscapes are often juxtaposed with...Sequoia and Kings Canyon Field Station
The Sequoia and Kings Canyon Field Station is home to research programs that focus on wildfire patterns in Southern California, and the effects of drought on Sierra Nevada forests. Select the "Science" tab for a more comprehensive summary. - Data
The Effect of Prolonged Drought on Chaparral Dieback within the Perimeters of the Thomas and Woolsey Fires in Southern California, USA
This dataset contains data pertaining to chaparral vegetation dieback based on the difference or change in the Normalized Difference Vegetation Index (NDVI) prior to and 6 years into an extensive drought before the 2017 Thomas and 2018 Woolsey Fires in southern California. The difference in mean NDVI is provided for 9322 study plots as are values for a number of physical and climatological variablThe Effect of Prolonged Drought on Chaparral Dieback within the Perimeters of the Thomas and Woolsey Fires in Southern California, USA
This dataset contains data pertaining to chaparral vegetation dieback based on the difference or change in the Normalized Difference Vegetation Index (NDVI) prior to and 6 years into an extensive drought before the 2017 Thomas and 2018 Woolsey Fires in southern California. The difference in mean NDVI is provided for 9322 study plots as are values for a number of physical and climatological variablData for Use in poscrptR Post-fire Conifer Regeneration Prediction Model
These data support poscrptR (Wright et al. 2021). poscrptR is a shiny app that predicts the probability of post-fire conifer regeneration for fire data supplied by the user. The predictive model was fit using presence/absence data collected in 4.4m radius plots (60 square meters). Please refer to Stewart et al. (2020) for more details concerning field data collection, the model fitting process, anSurvey Data for Chaparral Vegetation in Masticated Fuel Treatments on the four Southern California National Forests (2011-2012)
Mechanical fuel treatments are a primary pre-fire strategy for potentially mitigating the threat of wildland fire, yet there is limited information on how they impact shrubland ecosystems. This publication contains data related to vegetation structure and composition in mechanically masticated chaparral communities used to assess the impact of these fuel treatments on shrubland vegetation and to dVegetation type conversion in chaparral in San Diego County, California, USA between 1953 and 2016
This dataset contains data pertaining to ground surface cover in a 30 meter radius around a random selection of points within San Diego County, California. These data were obtained from aerial imagery for the years 1953 and 2016 and were used to assess changes in cover type over time. These data support the following publication: Syphard, A.D., Brennan, T.J. and Keeley, J.E., 2019. Extent aDemographic data for Hesperocyparis forbesii on Otay Mountain 2004-2017
This dataset contains demographic data pertaining to Hesperocyparis forbesii on Otay Mountain in San Diego County, California, USA, over a 14-year study period from 2004 to 2017 following the 2003 Otay/Mine Fire. Site variables including elevation, incline, and slope were collected as well as pre-fire tree density and stand age for 16 study site locations. Tree density, height, and cone productionChaparral Type Conversion into Herbaceous Vegetation in Coastal Southern California from 1947 to 2014, Data Compiled from Aerial Imagery, Geographic NAD83 (2017)
This dataset contains data pertaining to vegetation type, woody versus herbaceous versus non-vegetated, for a random selection of points within the Santa Monica Mountains National Recreation Area of Southern California. These data were obtained from aerial imagery for the years 1947, 1977, 1995, 2005, and 2014 and were used to determine changes in cover type over time. These data support the - Multimedia
- Publications
Filter Total Items: 351
Mechanisms of forest resilience
Ecosystems are dynamic systems with complex responses to environmental variation. In response to pervasive stressors of changing climate and disturbance regimes, many ecosystems are realigning rapidly across spatial scales, in many cases moving outside of their observed historical range of variation into alternative ecological states. In some cases, these new states are transitory and represent suLarge California wildfires: 2020 fires in historical context
BackgroundCalifornia in the year 2020 experienced a record breaking number of large fires. Here, we place this and other recent years in a historical context by examining records of large fire events in the state back to 1860. Since drought is commonly associated with large fire events, we investigated the relationship of large fire events to droughts over this 160 years period.ResultsThis study sIgnitions explain more than climate or weather in driving Santa Ana Wind fires
Autumn and winter Santa Ana wind (SAW)–driven wildfires play a substantial role in area burned and societal losses in southern California. Temperature during the event and antecedent precipitation in the week or month prior play a minor role in determining area burned. Burning is dependent on wind intensity and number of human-ignited fires. Over 75% of all SAW events generate no fires; rather, fiWildfires and global change
No single factor produces wildfires; rather, they occur when fire thresholds (ignitions, fuels, and drought) are crossed. Anomalous weather events may lower these thresholds and thereby enhance the likelihood and spread of wildfires. Climate change increases the frequency with which some of these thresholds are crossed, extending the duration of the fire season and increasing the frequency of dryU.S. Geological Survey wildland fire science strategic plan, 2021–26
The U.S. Geological Survey (USGS) Wildland Fire Science Strategic Plan defines critical, core fire science capabilities for understanding fire-related and fire-responsive earth system processes and patterns, and informing management decision making. Developed by USGS fire scientists and executive leadership, and informed by conversations with external stakeholders, the Strategic Plan is aligned wiByEcosystems, Natural Hazards, Earth Resources Observation and Science Center, Science Analytics and Synthesis (SAS), Alaska Science Center, Earth Resources Observation and Science (EROS) Center , Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Geologic Hazards Science Center, Geology, Geophysics, and Geochemistry Science Center, Western Ecological Research Center (WERC)Multiple-scale relationships between vegetation, the wildland–urban interface, and structure loss to wildfire in California
Recent increases in destructive wildfires are driving a need for empirical research documenting factors that contribute to structure loss. Existing studies show that fire risk is complex and varies geographically, and the role of vegetation has been especially difficult to quantify. Here, we evaluated the relative importance of vegetation cover at local (measured through the Normalized DifferenceContrasting prescription burning and wildfires in California Sierra Nevada national parks and adjacent national forests
History of prescription burning and wildfires in the three Sierra Nevada National Park Service (NPS) parks and adjacent US Forest Service (USFS) forests is presented. Annual prescription (Rx) burns began in 1968 in Sequoia and Kings Canyon National Parks, followed by Yosemite National Park and Lassen Volcanic National Park. During the last third of the 20th century, USFS national forests adjacentSeed production patterns of surviving Sierra Nevada conifers show minimal change following drought
Reproduction is a key component of ecological resilience in forest ecosystems, so understanding how seed production is influenced by extreme drought is key to understanding forest recovery trajectories. If trees respond to mortality-inducing drought by preferentially allocating resources for reproduction, the recovery of the stand to pre-drought conditions may be enhanced accordingly. We used a 20Effects of postfire climate and seed availability on postfire conifer regeneration
Large, severe fires are becoming more frequent in many forest types across the western United States and have resulted in tree mortality across tens of thousands of hectares. Conifer regeneration in these areas is limited because seeds must travel long distances to reach the interior of large burned patches and establishment is jeopardized by increasingly hot and dry conditions. To better inform pWhy are so many structures burning in California?
California has earned a reputation for wildfires that inflict serious damage on human infrastructure, dating back to images of Richard Nixon hosing down the roof of his house in the 1961 Bel-Air fire, and of the famous “fireproof” home of grocery store entrepreneur Fred Roberts burning to the ground in 1982. In recent years, this notoriety has been transformed into public alarm, reflected in the aSubspecies differentiation in an enigmatic chaparral shrub species
PremiseDelimiting biodiversity units is difficult in organisms in which differentiation is obscured by hybridization, plasticity, and other factors that blur phenotypic boundaries. Such work is more complicated when the focal units are subspecies, the definition of which has not been broadly explored in the era of modern genetic methods. Eastwood manzanita (Arctostaphylos glandulosa Eastw.) is a wProtecting the wildland-urban interface in California: Greenbelts vs thinning for wildfire threats to homes
This study utilized native chaparral and sage scrub shrubs to evaluate the impact of light summer irrigation on live fuel moisture content (LFMC) and predicted fire behavior. As to be expected LFMC varied markedly throughout the year being over 100% in winter in all species and treatments but differed markedly by treatment in the summer and fall. For most species lightly irrigated plants had the h - News
- Software
poscrptR
poscrptR is a simple R package with the sole purpose of distributing a shiny app for predicting post-fire conifer regeneration. Learn more about shiny apps here.Seed source, not drought, determines patterns of seed production in Sierra Nevada conifers
This release consists of data collected from 26 plots in two national parks over a 19-year period. The data consists of plot-level seed counts for three genera, number of seed traps, live tree basal area, plot area, and climate metrics from the gridmet gridded data set, the daymet gridded data set, the PRISM gridded data set, and two nearby COOP stations.