Wildfires statistics for the conterminous United States (U.S.) are examined in a spatially and temporally explicit manner. We use a high-resolution data set consisting of 88,916 U.S. Department of Agriculture Forest Service wildfires over the time period 1970-2000 and consider wildfire occurrence as a function of ecoregion (land units classified by climate, vegetation, and topography), ignition source (anthropogenic vs. lightning), and decade. For the conterminous U.S., we (i) find that wildfires exhibit robust frequency-area power-law behavior in 18 different ecoregions; (ii) use normalized power-law exponents to compare the scaling of wildfire-burned areas between ecoregions, finding a systematic change from east to west; (iii) find that wildfires in the eastern third of the U.S. have higher power-law exponents for anthropogenic vs. lightning ignition sources; and (iv) calculate recurrence intervals for wildfires of a given burned area or larger for each ecoregion, allowing for the classification of wildfire regimes for probabilistic hazard estimation in the same vein as is now used for earthquakes.
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http://dx.doi.org/10.1073/pnas.0500880102 | DOI Listing |
Retention forestry involves leaving single or groups of unharvested trees within harvest areas. Patch retention, which resembles structures such as unburned patches remaining after wildfire, is one practice implemented within the framework of Ecosystem-based Forest Management (EBM), which seeks to use natural forests as a model and minimize differences in natural and managed forests. Despite the widespread adoption of patch retention practices, few comparisons of the attributes of postfire and postharvest islands, or their drivers, have been made.
View Article and Find Full Text PDFEcol Appl
January 2025
Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Fire shapes biodiversity in many forested ecosystems, but historical management practices and anthropogenic climate change have led to larger, more severe fires that threaten many animal species where such disturbances do not occur naturally. As predators, owls can play important ecological roles in biological communities, but how changing fire regimes affect individual species and species assemblages is largely unknown. Here, we examined the impact of fire severity, history, and configuration over the past 35 years on an assemblage of six forest owl species in the Sierra Nevada, California, using ecosystem-scale passive acoustic monitoring.
View Article and Find Full Text PDFSci Total Environ
January 2025
Forest Fire Laboratory (LABIF), Forestry Engineering Department, University of Cordoba, 14071 Cordoba, Spain. Electronic address:
Most Mediterranean ecosystems have been profoundly shaped by wildfires, driving the evolution of plant species. Through photo interpretation and field inventories, this research assessed vegetation dynamics from 1984 to 2021, examining how fire severity and recurrence, key fire regime variables, influenced changes in structure and woody species diversity. Using two burn scars (1988 and 2006), we identified four scenarios dominated by Pinus pinea tree species: control (unburned), areas burned once (either in 1988 or 2006), and twice (in both 1988 and 2006).
View Article and Find Full Text PDFScience
January 2025
Valério D. Pillar is at the Laboratório de Ecologia Quantitativa, Departamento de Ecologia/Centro de Ecologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Over half of Earth's land surface is covered with fire-prone vegetation, with grassy ecosystems-such as grasslands, savannas, woodlands, and shrublands-being the most extensive. In the context of the climate crisis, scientists worldwide are exploring adaptation measures to address the heightened fire risk driven by more frequent extreme climatic conditions such as droughts and heatwaves, as well as by non-native plant invasions that increased fuel loads and altered fire regimes. Although fire is intrinsic to grassy ecosystems, rising exposure to wildfire smoke harms human health and the environment.
View Article and Find Full Text PDFEcosystems
January 2025
Oregon State University, Department of Forest Ecosystems & Society, Corvallis, Oregon USA.
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