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Stephens SL, Foster DE, Battles JJ, Bernal AA, Collins BM, Hedges R, Moghaddas JJ, Roughton AT, York RA. Forest restoration and fuels reduction work: Different pathways for achieving success in the Sierra Nevada. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2932. [PMID: 37948058 DOI: 10.1002/eap.2932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 06/20/2023] [Accepted: 10/03/2023] [Indexed: 11/12/2023]
Abstract
Fire suppression and past selective logging of large trees have fundamentally changed frequent-fire-adapted forests in California. The culmination of these changes produced forests that are vulnerable to catastrophic change by wildfire, drought, and bark beetles, with climate change exacerbating this vulnerability. Management options available to address this problem include mechanical treatments (Mech), prescribed fire (Fire), or combinations of these treatments (Mech + Fire). We quantify changes in forest structure and composition, fuel accumulation, modeled fire behavior, intertree competition, and economics from a 20-year forest restoration study in the northern Sierra Nevada. All three active treatments (Fire, Mech, Mech + Fire) produced forest conditions that were much more resistant to wildfire than the untreated control. The treatments that included prescribed fire (Fire, Mech + Fire) produced the lowest surface and duff fuel loads and the lowest modeled wildfire hazards. Mech produced low fire hazards beginning 7 years after the initial treatment and Mech + Fire had lower tree growth than controls. The only treatment that produced intertree competition somewhat similar to historical California mixed-conifer forests was Mech + Fire, indicating that stands under this treatment would likely be more resilient to enhanced forest stressors. While Fire reduced modeled wildfire hazard and reintroduced a fundamental ecosystem process, it was done at a net cost to the landowner. Using Mech that included mastication and restoration thinning resulted in positive revenues and was also relatively strong as an investment in reducing modeled wildfire hazard. The Mech + Fire treatment represents a compromise between the desire to sustain financial feasibility and the desire to reintroduce fire. One key component to long-term forest conservation will be continued treatments to maintain or improve the conditions from forest restoration. Many Indigenous people speak of "active stewardship" as one of the key principles in land management and this aligns well with the need for increased restoration in western US forests. If we do not use the knowledge from 20+ years of forest research and the much longer tradition of Indigenous cultural practices and knowledge, frequent-fire forests will continue to be degraded and lost.
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Affiliation(s)
- Scott L Stephens
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
| | - Daniel E Foster
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
| | - John J Battles
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
| | - Alexis A Bernal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
| | - Brandon M Collins
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
- Center for Fire Research and Outreach, University of California, Berkeley, Berkeley, California, USA
- USDA Forest Service, Pacific Southwest Region, Vallejo, California, USA
| | - Rachelle Hedges
- Berkeley Forests, University of California, Berkeley, Berkeley, California, USA
| | | | - Ariel T Roughton
- Berkeley Forests, University of California, Berkeley, Berkeley, California, USA
| | - Robert A York
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, California, USA
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2
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Kuntze CC, Pauli JN, Zulla CJ, Keane JJ, Roberts KN, Dotters BP, Sawyer SC, Peery MZ. Landscape heterogeneity provides co-benefits to predator and prey. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2908. [PMID: 37602901 DOI: 10.1002/eap.2908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 06/08/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Predator populations are imperiled globally, due in part to changing habitat and trophic interactions. Theoretical and laboratory studies suggest that heterogeneous landscapes containing prey refuges acting as source habitats can benefit both predator and prey populations, although the importance of heterogeneity in natural systems is uncertain. Here, we tested the hypothesis that landscape heterogeneity mediates predator-prey interactions between the California spotted owl (Strix occidentalis occidentalis)-a mature forest species-and one of its principal prey, the dusky-footed woodrat (Neotoma fuscipes)-a younger forest species-to the benefit of both. We did so by combining estimates of woodrat density and survival from live trapping and very high frequency tracking with direct observations of prey deliveries to dependent young by owls in both heterogeneous and homogeneous home ranges. Woodrat abundance was ~2.5 times higher in owl home ranges (14.12 km2 ) featuring greater heterogeneity in vegetation types (1805.0 ± 50.2 SE) compared to those dominated by mature forest (727.3 ± 51.9 SE), in large part because of high densities in young forests appearing to act as sources promoting woodrat densities in nearby mature forests. Woodrat mortality rates were low across vegetation types and did not differ between heterogeneous and homogeneous home ranges, yet all observed predation by owls occurred within mature forests, suggesting young forests may act as woodrat refuges. Owls exhibited a type 1 functional response, consuming ~2.5 times more woodrats in heterogeneous (31.1/month ± 5.2 SE) versus homogeneous (12.7/month ± 3.7 SE) home ranges. While consumption of smaller-bodied alternative prey partially compensated for lower woodrat consumption in homogeneous home ranges, owls nevertheless consumed 30% more biomass in heterogeneous home ranges-approximately equivalent to the energetic needs of producing one additional offspring. Thus, a mosaic of vegetation types including young forest patches increased woodrat abundance and availability that, in turn, provided energetic and potentially reproductive benefits to mature forest-associated spotted owls. More broadly, our findings provide strong empirical evidence that heterogeneous landscapes containing prey refuges can benefit both predator and prey populations. As anthropogenic activities continue to homogenize landscapes globally, promoting heterogeneous systems with prey refuges may benefit imperiled predators.
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Affiliation(s)
- Corbin C Kuntze
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA
| | - Jonathan N Pauli
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA
| | - Ceeanna J Zulla
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA
| | - John J Keane
- U.S. Forest Service, Pacific Southwest Research Station, Davis, California, USA
| | | | | | | | - M Zachariah Peery
- Department of Forest and Wildlife Ecology, University of Wisconsin, Madison, Wisconsin, USA
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3
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Dubinin M, Osem Y, Yakir D, Paz-Kagan T. Satellite-based assessment of water use and leaf area efficiencies of dryland conifer forests along an aridity gradient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:165977. [PMID: 37541509 DOI: 10.1016/j.scitotenv.2023.165977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/30/2023] [Accepted: 07/30/2023] [Indexed: 08/06/2023]
Abstract
Dryland forests worldwide are increasingly threatened by drought stress due to climate change. Understanding the relationships between forest structure and function is essential for managing dryland forests to adapt to these changes. We investigated the structure-function relationships in four dryland conifer forests distributed along a semiarid to subhumid climatic aridity gradient. Forest structure was represented by leaf area index (LAI) and function by gross primary productivity (GPP), evapotranspiration (ET), and the derived efficiencies of water use (WUE = GPP/ET) and leaf area (LAE = GPP/LAI). Estimates of GPP and ET were based on the observed relationships between high-resolution vegetation indices from VENμS and Sentinel-2A satellites and flux data from three eddy covariance towers in the study regions between November 2015 to October 2018. The red-edge-based MERIS Terrestrial Chlorophyll Index (MTCI) from VENμS and Sentinel-2A showed strong correlations to flux tower GPP and ET measurements for the three sites (R2cal > 0.91, R2val > 0.84). Using our approach, we showed that as LAI decreased with decreasing aridity index (AI) (i.e., dryer conditions), estimated GPP and ET decreased (R2 > 0.8 to LAI), while WUE (R2 = 0.68 to LAI) and LAE increased. The observed global-scale patterns are associated with a variety of forest vegetation characteristics, at the local scale, such as tree species composition and density. However, our results point towards a canopy-level mechanism, where the ecosystem-LAI and resultant proportion of sun-exposed vs. shaded leaves are primary determinants of WUE and LAE along the studied climatic aridity gradient. This work demonstrates the importance of high-resolution (spatially and spectrally) remote sensing data conjugated with flux tower data for monitoring dryland forests and understanding the intricate structure-function interactions in their response to drying conditions.
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Affiliation(s)
- Moshe Dubinin
- Earth and Planetary Sciences Department, Weizmann Institute, Rehovot, Israel; Department of Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Israel; French Associates Institute for Agriculture and Biotechnology of Dryland, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Israel
| | - Yagil Osem
- Department of Natural Resources, Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Israel
| | - Dan Yakir
- Earth and Planetary Sciences Department, Weizmann Institute, Rehovot, Israel
| | - Tarin Paz-Kagan
- French Associates Institute for Agriculture and Biotechnology of Dryland, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Israel.
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4
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Ursell T, Safford HD. Nucleation sites and forest recovery under high shrub competition. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2711. [PMID: 36161678 PMCID: PMC10078307 DOI: 10.1002/eap.2711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 05/05/2022] [Accepted: 05/23/2022] [Indexed: 06/16/2023]
Abstract
Forests currently face numerous stressors, raising questions about processes of forest recovery as well as the role of humans in stimulating recovery by planting trees that might not otherwise regenerate. Theoretically, planted trees can also provide a seed source for further recruitment once the planted trees become reproductive, acting as "nucleation" sites; however, it is unclear whether changing site conditions over time (e.g., through the growth of competitors like woody shrubs) influences establishment in the long term, even if seed availability increases. We tested the nucleation concept in a system where shrub competition is known to influence tree establishment and growth, performing an observational study of sites within and close to newly reproductive planted stands in yellow-pine (YP) and mixed-conifer ecosystems in the Sierra Nevada, California. We surveyed and then modeled both seedling occurrence and density as a function of distance to seed sources, competing woody vegetation, and other environmental characteristics. We found that proximity to a planted stand was associated with an increase in the probability of YP seedlings (species more likely to originate from the planted stand) from 0.33 at 35 m from the planted stand to 0.56 directly adjacent to the stand and 0.65 within the stand. However, we found no significant effect of proximity on YP seedling density. This proximity effect suggests that seed availability continues to be a driver of recruitment several decades postwildfire, though other processes may influence the expected density of recruits. Proxies for competitive pressure (shrub volume and shrub cover) were not significant, suggesting that competing vegetation did not have a major influence on recruitment. Though seedling presence and density appeared to be independent of shrub impacts, we did find that shrubs were significantly taller than seedlings. Therefore, we suggest that shrubs may not limit seedling establishment, but they may negatively affect seedlings' ability to grow and serve as a seed source for further recruitment and forest expansion. Altogether, we find that planting may provide a statistically significant but small role in driving recruitment outside of the planted site.
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Affiliation(s)
- Tara Ursell
- Graduate Group in EcologyUniversity of CaliforniaDavisCaliforniaUSA
| | - Hugh D. Safford
- Department of Environmental Science and PolicyUniversity of CaliforniaDavisCaliforniaUSA
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5
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Nemens DG, Kidd KR, Varner JM, Wing B. Recurring wildfires provoke type conversion in dry western forests. Ecosphere 2022. [DOI: 10.1002/ecs2.4184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Deborah G. Nemens
- School of Environmental and Forest Sciences University of Washington Seattle Washington USA
- Pacific Wildland Fire Sciences Laboratory USDA Forest Service Pacific Northwest Research Station Seattle Washington USA
| | - Kathryn R. Kidd
- Arthur Temple College of Forestry and Agriculture Stephen F. Austin State University Nacogdoches Texas USA
| | | | - Brian Wing
- USDA Forest Service Pacific Southwest Research Station Redding California USA
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6
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Food webs for three burn severities after wildfire in the Eldorado National Forest, California. Sci Data 2022; 9:384. [PMID: 35798761 PMCID: PMC9262949 DOI: 10.1038/s41597-022-01220-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 02/03/2022] [Indexed: 11/08/2022] Open
Abstract
Wildfire dynamics are changing around the world and understanding their effects on ecological communities and landscapes is urgent and important. We report detailed food webs for unburned, low-to-moderate and high severity burned habitats three years post-fire in the Eldorado National Forest, California. The cumulative cross-habitat food web contains 3,084 ontogenetic stages (nodes) or plant parts comprising 849 species (including 107 primary producers, 634 invertebrates, 94 vertebrates). There were 178,655 trophic interactions between these nodes. We provide information on taxonomy, body size, biomass density and trophic interactions under each of the three burn conditions. We detail 19 sampling methods deployed across 27 sites (nine in each burn condition) used to estimate the richness, body size, abundance and biomass density estimates in the node lists. We provide the R code and raw data to estimate summarized node densities and assign trophic links.
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7
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Keen RM, Voelker SL, Wang SYS, Bentz BJ, Goulden ML, Dangerfield CR, Reed CC, Hood SM, Csank AZ, Dawson TE, Merschel AG, Still CJ. Changes in tree drought sensitivity provided early warning signals to the California drought and forest mortality event. GLOBAL CHANGE BIOLOGY 2022; 28:1119-1132. [PMID: 34735729 DOI: 10.1111/gcb.15973] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Climate warming in recent decades has negatively impacted forest health in the western United States. Here, we report on potential early warning signals (EWS) for drought-related mortality derived from measurements of tree-ring growth (ring width index; RWI) and carbon isotope discrimination (∆13 C), primarily focused on ponderosa pine (Pinus ponderosa). Sampling was conducted in the southern Sierra Nevada Mountains, near the epicenter of drought severity and mortality associated with the 2012-2015 California drought and concurrent outbreak of western pine beetle (Dendroctonus brevicomis). At this site, we found that widespread mortality was presaged by five decades of increasing sensitivity (i.e., increased explained variation) of both tree growth and ∆13 C to Palmer Drought Severity Index (PDSI). We hypothesized that increasing sensitivity of tree growth and ∆13 C to hydroclimate constitute EWS that indicate an increased likelihood of widespread forest mortality caused by direct and indirect effects of drought. We then tested these EWS in additional ponderosa pine-dominated forests that experienced varying mortality rates associated with the same California drought event. In general, drier sites showed increasing sensitivity of RWI to PDSI over the last century, as well as higher mortality following the California drought event compared to wetter sites. Two sites displayed evidence that thinning or fire events that reduced stand basal area effectively reversed the trend of increasing hydroclimate sensitivity. These comparisons indicate that reducing competition for soil water and/or decreasing bark beetle host tree density via forest management-particularly in drier regions-may buffer these forests against drought stress and associated mortality risk. EWS such as these could provide land managers more time to mitigate the extent or severity of forest mortality in advance of droughts. Substantial efforts at deploying additional dendrochronological research in concert with remote sensing and forest modeling will aid in forecasting of forest responses to continued climate warming.
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Affiliation(s)
- Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Steven L Voelker
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan, USA
| | - S-Y Simon Wang
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Barbara J Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, Utah, USA
| | - Michael L Goulden
- Department of Earth System Science, University of California, Irvine, California, USA
| | - Cody R Dangerfield
- Department of Wildland Resources, Utah State University, Logan, Utah, USA
| | - Charlotte C Reed
- Fire Sciences Laboratory, USDA Forest Service, Rocky Mountain Research Station, Missoula, Montana, USA
| | - Sharon M Hood
- Fire Sciences Laboratory, USDA Forest Service, Rocky Mountain Research Station, Missoula, Montana, USA
| | - Adam Z Csank
- Department of Geography, University of Nevada, Reno, Nevada, USA
| | - Todd E Dawson
- Department of Environmental Science, Policy & Management, University of California, Berkeley, California, USA
| | - Andrew G Merschel
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, USA
| | - Christopher J Still
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, USA
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8
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Hagmann RK, Hessburg PF, Prichard SJ, Povak NA, Brown PM, Fulé PZ, Keane RE, Knapp EE, Lydersen JM, Metlen KL, Reilly MJ, Sánchez Meador AJ, Stephens SL, Stevens JT, Taylor AH, Yocom LL, Battaglia MA, Churchill DJ, Daniels LD, Falk DA, Henson P, Johnston JD, Krawchuk MA, Levine CR, Meigs GW, Merschel AG, North MP, Safford HD, Swetnam TW, Waltz AEM. Evidence for widespread changes in the structure, composition, and fire regimes of western North American forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02431. [PMID: 34339067 PMCID: PMC9285092 DOI: 10.1002/eap.2431] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/04/2021] [Accepted: 03/22/2021] [Indexed: 05/06/2023]
Abstract
Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.
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Affiliation(s)
- R. K. Hagmann
- College of the Environment‐SEFSUniversity of WashingtonSeattleWashington98195USA
- Applegate Forestry LLCCorvallisOregon97330USA
| | - P. F. Hessburg
- College of the Environment‐SEFSUniversity of WashingtonSeattleWashington98195USA
- USDA‐FS, Forestry Sciences LaboratoryPacific Northwest Research StationWenatcheeWashington98801USA
| | - S. J. Prichard
- College of the Environment‐SEFSUniversity of WashingtonSeattleWashington98195USA
| | - N. A. Povak
- USDA‐FS, Forestry Sciences LaboratoryPacific Northwest Research StationWenatcheeWashington98801USA
- USDA‐FS, Pacific Southwest Research StationPlacervilleCalifornia95667USA
| | - P. M. Brown
- Rocky Mountain Tree‐Ring ResearchFort CollinsColorado80526USA
| | - P. Z. Fulé
- School of ForestryNorthern Arizona UniversityFlagstaffArizona86011USA
| | - R. E. Keane
- Missoula Fire Sciences LaboratoryUSDA‐FS, Rocky Mountain Research StationMissoulaMontana59808USA
| | - E. E. Knapp
- USDA‐FS, Pacific Southwest Research StationReddingCalifornia96002USA
| | - J. M. Lydersen
- Fire and Resource Assessment ProgramCalifornia Department of Forestry and Fire ProtectionSacramentoCalifornia94244USA
| | | | - M. J. Reilly
- USDA‐FS, Pacific Northwest Research StationCorvallisOregon97333USA
| | - A. J. Sánchez Meador
- Ecological Restoration InstituteNorthern Arizona UniversityFlagstaffArizona86011USA
| | - S. L. Stephens
- Department of Environmental Science, Policy, and ManagementUniversity of California–BerkeleyBerkeleyCalifornia94720USA
| | - J. T. Stevens
- U.S. Geological SurveyFort Collins Science CenterNew Mexico Landscapes Field StationSanta FeNew Mexico87508USA
| | - A. H. Taylor
- Department of Geography, Earth and Environmental Systems InstituteThe Pennsylvania State UniversityUniversity ParkPennsylvania16802USA
| | - L. L. Yocom
- Department of Wildland Resources and the Ecology CenterUtah State UniversityLoganUtah84322USA
| | - M. A. Battaglia
- USDA‐FS, Rocky Mountain Research StationFort CollinsColorado80526USA
| | - D. J. Churchill
- Washington State Department of Natural ResourcesOlympiaWashington98504USA
| | - L. D. Daniels
- Department of Forest and Conservation SciencesUniversity of British ColumbiaVancouverBritish ColumbiaV6T 1Z4Canada
| | - D. A. Falk
- School of Natural Resources and the EnvironmentUniversity of ArizonaTucsonArizona85721USA
- Laboratory of Tree‐Ring ResearchUniversity of ArizonaTucsonArizona85721USA
| | - P. Henson
- Oregon Fish and Wildlife OfficeUSDI Fish & Wildlife ServicePortlandOregon97232USA
| | - J. D. Johnston
- College of ForestryOregon State UniversityCorvallisOregon97333USA
| | - M. A. Krawchuk
- College of ForestryOregon State UniversityCorvallisOregon97333USA
| | - C. R. Levine
- Spatial Informatics GroupPleasantonCalifornia94566USA
| | - G. W. Meigs
- Washington State Department of Natural ResourcesOlympiaWashington98504USA
| | - A. G. Merschel
- College of ForestryOregon State UniversityCorvallisOregon97333USA
| | - M. P. North
- USDA‐FS, Pacific Southwest Research StationMammoth LakesCalifornia93546USA
| | - H. D. Safford
- USDA‐FS, Pacific Southwest RegionVallejoCalifornia94592USA
| | - T. W. Swetnam
- Laboratory of Tree‐Ring ResearchUniversity of ArizonaTucsonArizona85721USA
| | - A. E. M. Waltz
- Ecological Restoration InstituteNorthern Arizona UniversityFlagstaffArizona86011USA
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9
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Abstract
The California Spotted Owl is an imperiled species that selects mature conifer forests for nesting and roosting while actively foraging in the “snag forest habitat” created when fire or drought kills most of the trees in patches. Federal agencies believe there are excess surface fuels in both of these habitat conditions in many of California’s forests due to fuel accumulation from decades of fire suppression and recent drought-related tree mortality. Accordingly, agencies such as the U.S. Forest Service are implementing widespread logging in Spotted Owl territories. While they acknowledge habitat degradation from such logging, and risks to the conservation of declining Spotted Owl populations, agencies hypothesize that such active forest management equates to effective fuel reduction that is needed to curb fire severity for the overall benefit of this at-risk species. In an initial investigation, I analyzed this issue in a large 2020 fire, the Creek Fire (153,738 ha), in the southern Sierra Nevada mountains of California. I found that pre-fire snag density was not correlated with burn severity. I also found that more intensive forest management was correlated to higher fire severity. My results suggest the fuel reduction approach is not justified and provide indirect evidence that such management represents a threat to Spotted Owls.
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10
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Collins BM, Bernal A, York RA, Stevens JT, Juska A, Stephens SL. Mixed-conifer forest reference conditions for privately owned timberland in the southern Cascade Range. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02400. [PMID: 34214228 DOI: 10.1002/eap.2400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/22/2021] [Accepted: 03/03/2021] [Indexed: 06/13/2023]
Abstract
The overwhelming majority of information on historical forest conditions in western North America comes from public lands, which may provide an incomplete description of historical landscapes. In this study we made use of an archive containing extensive timber survey data collected in the early 1920s from privately owned forestland. These data covered over 50,000 ha and effectively represent a 19% sample of the entire area. The historical forest conditions reconstructed from these data fit the classic model of frequent-fire forests: large trees, low density, and pine-dominated. However, unlike other large-scale forest reconstructions, our study area exhibited relatively low overall variability in forest structure and composition across the historical landscape. Despite having low variability, our analyses revealed evidence of biophysical controls on tree density and pine fraction. Annual climatic variables most strongly explained the range in historical tree densities, whereas historical pine fraction was explained by a combination of topographic and climatic variables. Contemporary forest inventory data collected from both public and private lands within the same general area, albeit not a direct remeasurement, revealed substantial increases in tree density and greatly reduced pine fractions relative to historical conditions. Contemporary forests exhibited a far greater range in these conditions than what existed historically. These findings suggest that private forestland managed with multiaged silviculture may be similar to public forestland with respect to departure in forest structure and compositions from that of historical forests. However, there may be differences between management objectives that favor timber production, more typical on private lands, vs. those that favor restoration, increasingly supported on public lands.
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Affiliation(s)
- Brandon M Collins
- U.S. Department of Agriculture Forest Service, Pacific Southwest Research Station, Davis, California, 95618, USA
- Center for Fire Research and Outreach, University of California, Berkeley, Berkeley, California, 94720-3114, USA
| | - Alexis Bernal
- Department of Environmental Science, Policy, and Management, Ecosystem Sciences Division, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Robert A York
- Department of Environmental Science, Policy, and Management, Ecosystem Sciences Division, University of California, Berkeley, Berkeley, California, 94720, USA
| | - Jens T Stevens
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Santa Fe, New Mexico, 87508, USA
| | - Andrew Juska
- Collins Pine Company, P.O. Box 796, Chester, California, 96020, USA
| | - Scott L Stephens
- Department of Environmental Science, Policy, and Management, Ecosystem Sciences Division, University of California, Berkeley, Berkeley, California, 94720, USA
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11
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Incorporating Shrub Neighborhood Dynamics to Predict Forest Succession Trajectories in an Altered Fire Regime. Ecosystems 2021. [DOI: 10.1007/s10021-021-00645-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Air Pollution and Climate Drive Annual Growth in Ponderosa Pine Trees in Southern California. CLIMATE 2021. [DOI: 10.3390/cli9050082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ponderosa pine (Pinus ponderosa, Douglas ex C. Lawson) is a climate-sensitive tree species dominant in the mixed conifer stands of the San Bernardino Mountains of California. However, the close proximity to the city of Los Angeles has resulted in extremely high levels of air pollution. Nitrogen (N) deposition, resulting from nitrous oxides emitted from incomplete combustion of fossil fuels, has been recorded in this region since the 1980s. The impact of this N deposition on ponderosa pine growth is complex and often obscured by other stressors including climate, bark beetle attack, and tropospheric ozone pollution. Here I use a 160-year-long (1855–2015) ponderosa pine tree ring chronology to examine the annual response of tree growth to both N deposition and climate in this region. The chronology is generated from 34 tree cores taken near Crestline, CA. A stepwise multiple regression between the tree ring chronology and various climate and air pollution stressors indicates that drought conditions at the end of the rainy season (March) and NO2 pollution during the water year (pOct-Sep) exhibit primary controls on growth (r2-adj = 0.65, p < 0.001). The direct correlation between NO2 and tree growth suggests that N deposition has a positive impact on ponderosa pine bole growth in this region. However, it is important to note that ozone, a known stressor to ponderosa pine trees, and NO2 are also highly correlated (r = 0.84, p < 0.05). Chronic exposure to both ozone and nitrogen dioxide may, therefore, have unexpected impacts on tree sensitivity to climate and other stressors in a warming world.
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13
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Steel ZL, Fogg AM, Burnett R, Roberts LJ, Safford HD. When bigger isn’t better—Implications of large high‐severity wildfire patches for avian diversity and community composition. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Zachary L. Steel
- Department of Environmental Science and Policy University of California Davis CA USA
- Department of Environmental Science, Policy, and Management University of California–Berkeley Berkeley CA USA
| | | | | | | | - Hugh D. Safford
- Department of Environmental Science and Policy University of California Davis CA USA
- United States Department of Agriculture Forest ServicePacific Southwest Region Vallejo CA USA
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14
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Jones GM, Gutiérrez RJ, Block WM, Carlson PC, Comfort EJ, Cushman SA, Davis RJ, Eyes SA, Franklin AB, Ganey JL, Hedwall S, Keane JJ, Kelsey R, Lesmeister DB, North MP, Roberts SL, Rockweit JT, Sanderlin JS, Sawyer SC, Solvesky B, Tempel DJ, Wan HY, Westerling AL, White GC, Peery MZ. Spotted owls and forest fire: Comment. Ecosphere 2020. [DOI: 10.1002/ecs2.3312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Gavin M. Jones
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - R. J. Gutiérrez
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
- Department of Fisheries, Wildlife, and Conservation Biology University of Minnesota St. Paul Minnesota USA
| | - William M. Block
- USDA Forest ServiceRocky Mountain Research Station Flagstaff Arizona USA
| | - Peter C. Carlson
- Department of Fish, Wildlife and Conservation Biology Colorado State University Fort Collins Colorado USA
| | - Emily J. Comfort
- College of Forestry Oregon State University Corvallis Oregon USA
| | - Samuel A. Cushman
- USDA Forest ServiceRocky Mountain Research Station Flagstaff Arizona USA
| | | | | | - Alan B. Franklin
- USDA National Wildlife Research Center Fort Collins Colorado USA
| | - Joseph L. Ganey
- USDA Forest ServiceRocky Mountain Research Station Flagstaff Arizona USA
| | - Shaula Hedwall
- US Fish and Wildlife ServiceArizona Fish & Wildlife Conservation Office Flagstaff Arizona USA
| | - John J. Keane
- USDA Forest ServicePacific Southwest Research Station Davis California USA
| | - Rodd Kelsey
- The Nature Conservancy Sacramento California USA
| | | | - Malcolm P. North
- USDA Forest ServicePacific Southwest Research Station Davis California USA
- The John Muir Institute University of California Davis California USA
| | | | - Jeremy T. Rockweit
- Department of Fish, Wildlife and Conservation Biology Colorado State University Fort Collins Colorado USA
| | - Jamie S. Sanderlin
- USDA Forest ServiceRocky Mountain Research Station Flagstaff Arizona USA
| | | | - Ben Solvesky
- Sierra Forest Legacy Garden Valley California USA
| | - Douglas J. Tempel
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - Ho Yi Wan
- School of Public and Community Health Sciences University of Montana Missoula Montana USA
| | - A. LeRoy Westerling
- Sierra Nevada Research Institute University of California Merced California USA
| | - Gary C. White
- Department of Fish, Wildlife and Conservation Biology Colorado State University Fort Collins Colorado USA
| | - M. Zachariah Peery
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
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15
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Stephens SL, Battaglia MA, Churchill DJ, Collins BM, Coppoletta M, Hoffman CM, Lydersen JM, North MP, Parsons RA, Ritter SM, Stevens JT. Forest Restoration and Fuels Reduction: Convergent or Divergent? Bioscience 2020. [DOI: 10.1093/biosci/biaa134] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
For over 20 years, forest fuel reduction has been the dominant management action in western US forests. These same actions have also been associated with the restoration of highly altered frequent-fire forests. Perhaps the vital element in the compatibility of these treatments is that both need to incorporate the salient characteristics that frequent fire produced—variability in vegetation structure and composition across landscapes and the inability to support large patches of high-severity fire. These characteristics can be achieved with both fire and mechanical treatments. The possible key to convergence of fuel reduction and forest restoration strategies is integrated planning that permits treatment design flexibility and a longer-term focus on fire reintroduction for maintenance. With changing climate conditions, long-term forest conservation will probably need to be focused on keeping tree density low enough (i.e., in the lower range of historic variation) for forest conditions to adapt to emerging disturbance patterns and novel ecological processes.
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Affiliation(s)
- Scott L Stephens
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, in Berkeley, California
| | - Mike A Battaglia
- US Department of Agriculture (USDA), Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado
| | - Derek J Churchill
- Forest Health and Resiliency Division of the Washington Department of Natural Resources, Olympia, Washington
| | - Brandon M Collins
- Fire Research and Outreach at the University of California, Berkeley, Berkeley, California, and with the USDA Forest Service, Pacific Southwest Research Station, Davis, California
| | - Michelle Coppoletta
- USDA Forest Service, Sierra Cascade Province Ecology Program, Quincy, California
| | - Chad M Hoffman
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, Colorado
| | - Jamie M Lydersen
- California Department of Forestry and Fire Protection, Fire and Resource Assessment Program, Sacramento, California
| | - Malcolm P North
- USDA Forest Service, PSW Research Station, Mammoth Lakes, California, and with the Department of Plant Sciences, University of California, Davis, Davis, California
| | | | - Scott M Ritter
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, Colorado
| | - Jens T Stevens
- US Geological Survey, New Mexico Landscapes Field Station, Santa Fe, New Mexico
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16
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Keen RM, Voelker SL, Bentz BJ, Wang SYS, Ferrell R. Stronger influence of growth rate than severity of drought stress on mortality of large ponderosa pines during the 2012-2015 California drought. Oecologia 2020; 194:359-370. [PMID: 33030569 DOI: 10.1007/s00442-020-04771-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022]
Abstract
Forests in the western United States are being subject to more frequent and severe drought events as the climate warms. The 2012-2015 California drought is a recent example, whereby drought stress was exacerbated by a landscape-scale outbreak of western pine beetle (Dendroctonus brevicomis) and resulted in widespread mortality of dominant canopy species including ponderosa pine (Pinus ponderosa). In this study, we compared pairs of large surviving and beetle-killed ponderosa pines following the California drought in the southern Sierra Nevadas to evaluate physiological characteristics related to survival. Inter-annual growth rates and tree-ring stable isotopes (∆13C and δ18O) were utilized to compare severity of drought stress and climate sensitivity in ponderosa pines that survived and those that were killed by western pine beetle. Compared to beetle-killed trees, surviving trees had higher growth rates and grew in plots with lower ponderosa pine basal area. However, there were no detectable differences in tree-ring ∆13C, δ18O, or stable isotope sensitivity to drought-related meteorological variables. These results indicate that differences in severity of drought stress had little influence on local, inter-tree differences in growth rate and survival of large ponderosa pines during this drought event. Many previous studies have shown that large trees are more likely to be attacked and killed by bark beetles compared to small trees. Our results further suggest that among large ponderosa pines, those that were more resistant to drought stress and bark beetle attacks were in the upper echelon of growth rates among trees within a stand and across the landscape.
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Affiliation(s)
- Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, KS, USA.
| | - Steve L Voelker
- Department of Environmental and Forest Biology, SUNY ESF, Syracuse, NY, USA
| | - Barbara J Bentz
- USDA Forest Service, Rocky Mountain Research Station, Logan, UT, USA
| | - S-Y Simon Wang
- Department of Plants, Soils and Climate, Utah State University, Logan, UT, USA
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17
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Knight CA, Cogbill CV, Potts MD, Wanket JA, Battles JJ. Settlement‐era forest structure and composition in the Klamath Mountains: reconstructing a historical baseline. Ecosphere 2020. [DOI: 10.1002/ecs2.3250] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Clarke A. Knight
- Department of Environmental Science, Policy, and Management University of California, Berkeley Berkeley California94720USA
| | | | - Matthew D. Potts
- Department of Environmental Science, Policy, and Management University of California, Berkeley Berkeley California94720USA
| | - James A. Wanket
- Department of Geography California State University, Sacramento Sacramento California95819USA
| | - John J. Battles
- Department of Environmental Science, Policy, and Management University of California, Berkeley Berkeley California94720USA
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18
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Foster DE, Battles JJ, Collins BM, York RA, Stephens SL. Potential wildfire and carbon stability in frequent‐fire forests in the Sierra Nevada: trade‐offs from a long‐term study. Ecosphere 2020. [DOI: 10.1002/ecs2.3198] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Daniel E. Foster
- Ecosystem Sciences Division Department of Environmental Science, Policy, and Management University of California Berkeley California94720USA
| | - John J. Battles
- Ecosystem Sciences Division Department of Environmental Science, Policy, and Management University of California Berkeley California94720USA
| | - Brandon M. Collins
- Center for Fire Research and Outreach University of California Berkeley California94720USA
- USDA Forest Service Pacific Southwest Research Station Davis California95618USA
| | - Robert A. York
- Ecosystem Sciences Division Department of Environmental Science, Policy, and Management University of California Berkeley California94720USA
| | - Scott L. Stephens
- Ecosystem Sciences Division Department of Environmental Science, Policy, and Management University of California Berkeley California94720USA
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19
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Beller EE, McClenachan L, Zavaleta ES, Larsen LG. Past forward: Recommendations from historical ecology for ecosystem management. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2019.e00836] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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20
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Young DJN, Meyer M, Estes B, Gross S, Wuenschel A, Restaino C, Safford HD. Forest recovery following extreme drought in California, USA: natural patterns and effects of pre-drought management. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02002. [PMID: 31519065 DOI: 10.1002/eap.2002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/14/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
Rising temperatures and more frequent and severe droughts are driving increases in tree mortality in forests around the globe. However, in many cases, the likely trajectories of forest recovery following drought-related mortality are poorly understood. In many fire-suppressed western U.S. forests, management is applied to reverse densification and restore natural forest structure and species composition, but it is unclear how such management affects post-mortality recovery. We addressed these uncertainties by examining forest stands that experienced mortality during the severe drought of 2012-2016 in California, USA. We surveyed post-drought vegetation along a gradient of overstory mortality severity in paired treated (mechanically thinned or prescribed-burned) and untreated areas in the Sierra Nevada. Treatment substantially reduced tree density, particularly in smaller tree size classes, and these effects persisted through severe drought-related overstory mortality. However, even in treated areas with severe mortality (>67% basal area mortality), the combined density of residual (surviving) trees (mean 44 trees/ha) and saplings (mean 189 saplings/ha) frequently (86% of plots) fell within or exceeded the natural range of variation (NRV) of tree density, suggesting little need for reforestation intervention to increase density. Residual tree densities in untreated high-mortality plots were significantly higher (mean 192 trees/ha and 506 saplings/ha), and 96% of these plots met or exceeded the NRV. Treatment disproportionately removed shade-tolerant conifer species, while mortality in the drought event was concentrated in pines (Pinus ponderosa and P. lambertiana); as a consequence, the residual trees, saplings, and seedlings in treated areas, particularly those that had experienced moderate or high drought-related mortality, were more heavily dominated by broadleaf ("hardwood") trees (particularly Quercus kelloggii and Q. chrysolepis). In contrast, residual trees and regeneration in untreated stands were heavily dominated by shade-tolerant conifer species (Abies concolor and Calocedrus decurrens), suggesting a need for future treatment. Because increased dominance of hardwoods brings benefits for plant and animal diversity and stand resilience, the ecological advantages of mechanical thinning and prescribed fire treatments may, depending on the management perspective, extend even to stands that ultimately experience high drought-related mortality following treatment.
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Affiliation(s)
- Derek J N Young
- Department of Environmental Science and Policy, University of California, Davis, Davis, California, 95616, USA
| | - Marc Meyer
- USDA Forest Service, Pacific Southwest Region, Southern Sierra Province, Bishop, California, 93514, USA
| | - Becky Estes
- USDA Forest Service, Pacific Southwest Region, Central Sierra Province, Placerville, California, 95667, USA
| | - Shana Gross
- USDA Forest Service, Pacific Southwest Region, Central Sierra Province, South Lake Tahoe, California, 96150, USA
| | - Amarina Wuenschel
- USDA Forest Service, Pacific Southwest Region, Southern Sierra Province, Clovis, California, 93611, USA
| | - Christina Restaino
- Department of Environmental Science and Policy, University of California, Davis, Davis, California, 95616, USA
| | - Hugh D Safford
- Department of Environmental Science and Policy, University of California, Davis, Davis, California, 95616, USA
- USDA Forest Service, Pacific Southwest Region, Vallejo, California, 94592, USA
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21
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Meunier J, Holoubek NS, Brown PM, Sebasky M. Re-evaluating pattern and process to understand resilience in transitional mixed conifer forests. Ecology 2019; 100:e02839. [PMID: 31330049 DOI: 10.1002/ecy.2839] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/16/2019] [Accepted: 06/25/2019] [Indexed: 11/08/2022]
Abstract
A key challenge to maintaining resilient landscapes is adapting to and maintaining dynamic ecological processes. In fire-dependent ecosystems, this includes identifying and defining mechanisms through which fire influences forest structure and functionality. Interpretations of tree patterns via land survey records in the Lake States have often highlighted the importance of infrequent moderate to extreme disturbance events. However, historical survey methods are limited to observing higher severity disturbances and over large landscapes, thus it is not clear if the origin, structure, and forcing factors for either patterns or processes are adequately quantified by these methods. We used dendrochronological methods to determine how fire history and stand structure, including cohort structure, tree density, and spatial patterning, are linked within Lake States mixed conifer forests in Wisconsin. We found relatively short mean fire return intervals (MFRIs) ranging from 6 to 13 yr with little variation in fire frequency among sites. Current densities of red-pine-dominated forests are 4-37 times historical (ca. 1860) densities (mean 12×) and almost entirely spatially random, whereas historically forests were spatially aggregated at stand scales. Stands also contained multiple and/or loosely defined cohort structures suggesting very different controls operating historically than currently. Heterogeneity that helped maintain ecosystem resilience in these ecosystems historically came from frequent fire disturbance processes that affected stand-scale forest resistance. This was likely the historical dynamic across fire-adapted transitional pine forests of the Lake States.
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Affiliation(s)
- Jed Meunier
- Wisconsin Department of Natural Resources, Division of Forestry, 2801 Progress Road, Madison, Wisconsin, 53716, USA
| | - Nathan S Holoubek
- Wisconsin Department of Natural Resources, Division of Forestry, 2801 Progress Road, Madison, Wisconsin, 53716, USA
| | - Peter M Brown
- Rocky Mountain Tree-Ring Research, 2901 Moore Lane, Fort Collins, Colorado, 80526, USA
| | - Megan Sebasky
- Wisconsin Department of Natural Resources, Division of Forestry, 2801 Progress Road, Madison, Wisconsin, 53716, USA
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22
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Grain and Extent Considerations Are Integral for Monitoring Landscape-Scale Desired Conditions in Fire-Adapted Forests. FORESTS 2019. [DOI: 10.3390/f10060465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Remotely-sensed data are commonly used to evaluate forest metrics, such as canopy cover, to assess change detection, and to inform land management planning. Often, canopy cover is measured only at the scale of the spatial data product used in the analysis, and there is a mismatch between the management question and the scale of the data. We compared four readily available remotely sensed landscape data products— Light detection and ranging (LiDAR), Landsat-8, Sentinel-2, and National Agriculture Imagery Program (NAIP) imagery —at different spatial grains and multiple extents to assess their consistency and efficacy for quantifying key landscape characteristics of forest canopy patches and sensitivity to change. We examined landscape-scale patterns of forest canopy cover across three landscapes in northern Arizona and assessed their performance using six landscape metrics. Changes in grain and extent affect canopy cover patch metrics and the inferences that can be made from each data product. Overall data products performed differently across landscape metrics. When performing analyses and choosing data layers, it is essential to match the scale of the data product to the management question and understand the limitations inherent in using canopy cover as a stand-alone metric.
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23
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Johnston JD, Dunn CJ, Vernon MJ, Bailey JD, Morrissette BA, Morici KE. Restoring historical forest conditions in a diverse inland Pacific Northwest landscape. Ecosphere 2018. [DOI: 10.1002/ecs2.2400] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- James D. Johnston
- College of Forestry; Oregon State University; 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - Christopher J. Dunn
- College of Forestry; Oregon State University; 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - Michael J. Vernon
- Department of Forestry and Wildland Resources; Humboldt State University; 1 Harpst Street Arcata California 95521 USA
| | - John D. Bailey
- College of Forestry; Oregon State University; 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - Brett A. Morrissette
- College of Forestry; Oregon State University; 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - Kat E. Morici
- Department of Forest and Rangeland Stewardship; Colorado Forest Restoration Institute; Colorado State University; 1472 Campus Delivery Fort Collins Colorado 80523 USA
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24
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Hagmann RK, Stevens JT, Lydersen JM, Collins BM, Battles JJ, Hessburg PF, Levine CR, Merschel AG, Stephens SL, Taylor AH, Franklin JF, Johnson DL, Johnson KN. Improving the use of early timber inventories in reconstructing historical dry forests and fire in the western United States: Comment. Ecosphere 2018. [DOI: 10.1002/ecs2.2232] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- R. Keala Hagmann
- Applegate Forestry LLC; 28831 Tampico Road Corvallis Oregon 97330 USA
- School of Environmental and Forest Sciences; University of Washington; Seattle Washington 98195 USA
| | - Jens T. Stevens
- Ecosystem Sciences Division; Department of Environmental Science, Policy, and Management; University of California; Berkeley California 94720 USA
| | - Jamie M. Lydersen
- Ecosystem Sciences Division; Department of Environmental Science, Policy, and Management; University of California; Berkeley California 94720 USA
| | - Brandon M. Collins
- Center for Fire Research and Outreach; University of California; Berkeley California 94720 USA
| | - John J. Battles
- Ecosystem Sciences Division; Department of Environmental Science, Policy, and Management; University of California; Berkeley California 94720 USA
| | - Paul F. Hessburg
- School of Environmental and Forest Sciences; University of Washington; Seattle Washington 98195 USA
- USDA-FS, Pacific Northwest Research Station; Wenatchee Washington 98801 USA
| | - Carrie R. Levine
- Department of Environmental Science and Policy; University of California; Davis California 95616 USA
| | - Andrew G. Merschel
- Department of Forest Engineering Resources and Management; College of Forestry; Oregon State University; Corvallis Oregon 97333 USA
| | - Scott L. Stephens
- Ecosystem Sciences Division; Department of Environmental Science, Policy, and Management; University of California; Berkeley California 94720 USA
| | - Alan H. Taylor
- Department of Geography, Earth and Environmental Institute; The Pennsylvania State University; University Park Pennsylvania 16802 USA
| | - Jerry F. Franklin
- School of Environmental and Forest Sciences; University of Washington; Seattle Washington 98195 USA
| | - Debora L. Johnson
- Applegate Forestry LLC; 28831 Tampico Road Corvallis Oregon 97330 USA
| | - K. Norman Johnson
- Department of Forest Ecosystems and Society; Oregon State University; Corvallis Oregon 97331 USA
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25
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Baker WL, Hanson CT, Williams MA. Improving the use of early timber inventories in reconstructing historical dry forests and fire in the western United States: Reply. Ecosphere 2018. [DOI: 10.1002/ecs2.2325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- William L. Baker
- Program in Ecology/Department of Geography; University of Wyoming; Laramie Wyoming 82071 USA
| | - Chad T. Hanson
- Earth Island Institute; 2150 Allston Way, Suite 460 Berkeley California 94704 USA
| | - Mark A. Williams
- Program in Ecology/Department of Geography; University of Wyoming; Laramie Wyoming 82071 USA
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26
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Baker WL, Williams MA. Land surveys show regional variability of historical fire regimes and dry forest structure of the western United States. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:284-290. [PMID: 29345744 DOI: 10.1002/eap.1688] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 12/03/2017] [Accepted: 12/21/2017] [Indexed: 06/07/2023]
Abstract
An understanding of how historical fire and structure in dry forests (ponderosa pine, dry mixed conifer) varied across the western United States remains incomplete. Yet, fire strongly affects ecosystem services, and forest restoration programs are underway. We used General Land Office survey reconstructions from the late 1800s across 11 landscapes covering ~1.9 million ha in four states to analyze spatial variation in fire regimes and forest structure. We first synthesized the state of validation of our methods using 20 modern validations, 53 historical cross-validations, and corroborating evidence. These show our method creates accurate reconstructions with low errors. One independent modern test reported high error, but did not replicate our method and made many calculation errors. Using reconstructed parameters of historical fire regimes and forest structure from our validated methods, forests were found to be non-uniform across the 11 landscapes, but grouped together in three geographical areas. Each had a mixture of fire severities, but dominated by low-severity fire and low median tree density in Arizona, mixed-severity fire and intermediate to high median tree density in Oregon-California, and high-severity fire and intermediate median tree density in Colorado. Programs to restore fire and forest structure could benefit from regional frameworks, rather than one size fits all.
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Affiliation(s)
- William L Baker
- Program in Ecology/Department of Geography, University of Wyoming, Department 3371, 1000 East University Avenue, Laramie, Wyoming, 82071, USA
| | - Mark A Williams
- Program in Ecology/Department of Geography, University of Wyoming, Department 3371, 1000 East University Avenue, Laramie, Wyoming, 82071, USA
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27
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Lydersen JM, Collins BM. Change in Vegetation Patterns Over a Large Forested Landscape Based on Historical and Contemporary Aerial Photography. Ecosystems 2018. [DOI: 10.1007/s10021-018-0225-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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28
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Stephens SL, Collins BM, Fettig CJ, Finney MA, Hoffman CM, Knapp EE, North MP, Safford H, Wayman RB. Drought, Tree Mortality, and Wildfire in Forests Adapted to Frequent Fire. Bioscience 2018. [DOI: 10.1093/biosci/bix146] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Scott L Stephens
- Department of Environmental Science, Policy, and Management at the University of California, in Berkeley
| | - Brandon M Collins
- Center for Fire Research and Outreach at the University of California, in Berkeley
| | - Christopher J Fettig
- US Department of Agriculture (USDA) Forest Service, Pacific Southwest Research Station, in Davis, California
| | - Mark A Finney
- USDA Forest Service, Rocky Mountain Research Station, in Missoula, Montana
| | - Chad M Hoffman
- Department of Forest and Range Stewardship at Colorado State University, in Fort Collins
| | - Eric E Knapp
- USDA Forest Service, Pacific Southwest Research Station, in Redding, California
| | - Malcolm P North
- US Department of Agriculture (USDA) Forest Service, Pacific Southwest Research Station, in Davis, California
| | - Hugh Safford
- Department of Environmental Science and Policy at the University of California, in Davis
- HS is also with the USDA Forest Service, Pacific Southwest Region, in Vallejo, California
| | - Rebecca B Wayman
- Department of Environmental Science and Policy at the University of California, in Davis
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29
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Jones GM, Keane JJ, Gutiérrez RJ, Peery MZ. Declining old-forest species as a legacy of large trees lost. DIVERS DISTRIB 2017. [DOI: 10.1111/ddi.12682] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Gavin M. Jones
- Department of Forest & Wildlife Ecology; University of Wisconsin-Madison; Madison WI USA
| | - John J. Keane
- U.S.D.A. Forest Service, Pacific Southwest Research Station; Davis CA USA
| | - R. J. Gutiérrez
- Department of Forest & Wildlife Ecology; University of Wisconsin-Madison; Madison WI USA
- Department of Fisheries, Wildlife and Conservation Biology; University of Minnesota; St. Paul MN USA
| | - M. Zachariah Peery
- Department of Forest & Wildlife Ecology; University of Wisconsin-Madison; Madison WI USA
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30
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Collins BM, Fry DL, Lydersen JM, Everett R, Stephens SL. Impacts of different land management histories on forest change. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:2475-2486. [PMID: 28873261 DOI: 10.1002/eap.1622] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/07/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
Many western North American forest types have experienced considerable changes in ecosystem structure, composition, and function as a result of both fire exclusion and timber harvesting. These two influences co-occurred over a large portion of dry forests, making it difficult to know the strength of either one on its own or the potential for an interaction between the two. In this study, we used contemporary remeasurements of a systematic historical forest inventory to investigate forest change in the Sierra Nevada. The historical data opportunistically spanned a significant land management agency boundary, which protected part of the inventory area from timber harvesting. This allowed for a robust comparison of forest change between logged and unlogged areas. In addition, we assessed the effects of recent management activities aimed at forest restoration relative to the same areas historically, and to other areas without recent management. Based on analyses of 22,007 trees (historical, 9,573; contemporary, 12,434), live basal area and tree density significantly increased from 1911 to the early 2000s in both logged and unlogged areas. Both shrub cover and the proportion of live basal area occupied by pine species declined from 1911 to the early 2000s in both areas, but statistical significance was inconsistent. The most notable difference between logged and unlogged areas was in the density of large trees, which declined significantly in logged areas, but was unchanged in unlogged areas. Recent management activities had a varied impact on the forest structure and composition variables analyzed. In general, areas with no recent management activities experienced the greatest change from 1911 to the early 2000s. If approximating historical forest conditions is a land management goal the documented changes in forest structure and composition from 1911 to the early 2000s indicate that active restoration, including fire use and mechanical thinning, is needed in many areas.
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Affiliation(s)
- Brandon M Collins
- Center for Fire Research and Outreach, University of California, Berkeley, California, 94720-3114, USA
| | - Danny L Fry
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, 94720, USA
| | - Jamie M Lydersen
- Pacific Southwest Research Station, USDA Forest Service, Davis, California, 95618, USA
| | - Richard Everett
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, 94720, USA
- Department of Natural Resources, Salish Kootenai College, 58138 Highway 93, P.O. Box 70, Pablo, Montana, 59855, USA
| | - Scott L Stephens
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, 94720, USA
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Harris L, Taylor AH. Previous burns and topography limit and reinforce fire severity in a large wildfire. Ecosphere 2017. [DOI: 10.1002/ecs2.2019] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Lucas Harris
- Department of Geography; Pennsylvania State University; 302 Walker Building University Park Pennsylvania 16802 USA
| | - Alan H. Taylor
- Department of Geography; Pennsylvania State University; 302 Walker Building University Park Pennsylvania 16802 USA
- Earth and Environmental Systems Institute; Pennsylvania State University; 2217 Earth-Engineering Sciences Building University Park Pennsylvania 16802 USA
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Freeman J, Kobziar L, Rose EW, Cropper W. A critique of the historical-fire-regime concept in conservation. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:976-985. [PMID: 28370371 DOI: 10.1111/cobi.12942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/02/2016] [Accepted: 01/04/2017] [Indexed: 06/07/2023]
Abstract
Prescribed fire is widely accepted as a conservation tool because fire is essential to the maintenance of native biodiversity in many terrestrial communities. Approaches to this land-management technique vary greatly among continents, and sharing knowledge internationally can inform application of prescribed fire worldwide. In North America, decisions about how and when to apply prescribed fire are typically based on the historical-fire-regime concept (HFRC), which holds that replicating the pattern of fires ignited by lightning or preindustrial humans best promotes native species in fire-prone regions. The HFRC rests on 3 assumptions: it is possible to infer historical fire regimes accurately; fire-suppressed communities are ecologically degraded; and reinstating historical fire regimes is the best course of action despite the global shift toward novel abiotic and biotic conditions. We examined the underpinnings of these assumptions by conducting a literature review on the use of historical fire regimes to inform the application of prescribed fire. We found that the practice of inferring historical fire regimes for entire regions or ecosystems often entails substantial uncertainty and can yield equivocal results; ecological outcomes of fire suppression are complex and may not equate to degradation, depending on the ecosystem and context; and habitat fragmentation, invasive species, and other modern factors can interact with fire to produce novel and in some cases negative ecological outcomes. It is therefore unlikely that all 3 assumptions will be fully upheld for any landscape in which prescribed fire is being applied. Although the HFRC is a valuable starting point, it should not be viewed as the sole basis for developing prescribed fire programs. Rather, fire prescriptions should also account for other specific, measurable ecological parameters on a case-by-case basis. To best achieve conservation goals, researchers should seek to understand contemporary fire-biota interactions across trophic levels, functional groups, spatial and temporal scales, and management contexts.
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Affiliation(s)
- Johanna Freeman
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Lovett E. Williams Jr. Wildlife Research Laboratory, 1105 SW Williston Road, Gainesville, FL, 32601, U.S.A
- School of Forest Resources and Conservation, University of Florida, 214 Newins-Ziegler Hall, P.O. Box 110410, Gainesville, FL, 32611, U.S.A
| | - Leda Kobziar
- Department of Natural Resources and Society, University of Idaho, 875 Perimeter Drive MS 1139, Moscow, ID, 83844-1139, U.S.A
| | - Elizabeth White Rose
- School of Natural Resources and Environment, University of Florida, 110 Newins-Ziegler Hall, P.O. Box 110430, Gainesville, FL, 32611, U.S.A
| | - Wendell Cropper
- School of Forest Resources and Conservation, University of Florida, 214 Newins-Ziegler Hall, P.O. Box 110410, Gainesville, FL, 32611, U.S.A
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Structure and Composition of a Dry Mixed-Conifer Forest in Absence of Contemporary Treatments, Southwest, USA. FORESTS 2017. [DOI: 10.3390/f8090349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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34
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Baker WL, Hanson CT. Improving the use of early timber inventories in reconstructing historical dry forests and fire in the western United States. Ecosphere 2017. [DOI: 10.1002/ecs2.1935] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- William L. Baker
- Program in Ecology/Department of Geography; University of Wyoming; Laramie Wyoming 82071 USA
| | - Chad T. Hanson
- Earth Island Institute; 2150 Allston Way, Suite 460 Berkeley California 94704 USA
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Swetnam TW, Farella J, Roos CI, Liebmann MJ, Falk DA, Allen CD. Multiscale perspectives of fire, climate and humans in western North America and the Jemez Mountains, USA. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0168. [PMID: 27216525 PMCID: PMC4874406 DOI: 10.1098/rstb.2015.0168] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2016] [Indexed: 11/16/2022] Open
Abstract
Interannual climate variations have been important drivers of wildfire occurrence in ponderosa pine forests across western North America for at least 400 years, but at finer scales of mountain ranges and landscapes human land uses sometimes over-rode climate influences. We reconstruct and analyse effects of high human population densities in forests of the Jemez Mountains, New Mexico from ca 1300 CE to Present. Prior to the 1680 Pueblo Revolt, human land uses reduced the occurrence of widespread fires while simultaneously adding more ignitions resulting in many small-extent fires. During the 18th and 19th centuries, wet/dry oscillations and their effects on fuels dynamics controlled widespread fire occurrence. In the late 19th century, intensive livestock grazing disrupted fuels continuity and fire spread and then active fire suppression maintained the absence of widespread surface fires during most of the 20th century. The abundance and continuity of fuels is the most important controlling variable in fire regimes of these semi-arid forests. Reduction of widespread fires owing to reduction of fuel continuity emerges as a hallmark of extensive human impacts on past forests and fire regimes. This article is part of the themed issue ‘The interaction of fire and mankind’.
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Affiliation(s)
- Thomas W Swetnam
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA
| | - Joshua Farella
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA
| | - Christopher I Roos
- Department of Anthropology, Southern Methodist University, Dallas, TX, USA
| | | | - Donald A Falk
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA School of Natural Resources and Environment, University of Arizona, Tucson, AZ 85721, USA
| | - Craig D Allen
- US Geological Survey, Jemez Mountains Field Station, Los Alamos, NM, USA
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Levine CR, Cogbill CV, Collins BM, Larson AJ, Lutz JA, North MP, Restaino CM, Safford HD, Stephens SL, Battles JJ. Evaluating a new method for reconstructing forest conditions from General Land Office survey records. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:1498-1513. [PMID: 28370925 DOI: 10.1002/eap.1543] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 02/22/2017] [Indexed: 06/07/2023]
Abstract
Historical forest conditions are often used to inform contemporary management goals because historical forests are considered to be resilient to ecological disturbances. The General Land Office (GLO) surveys of the late 19th and early 20th centuries provide regionally quasi-contiguous data sets of historical forests across much of the Western United States. Multiple methods exist for estimating tree density from point-based sampling such as the GLO surveys, including distance-based and area-based approaches. Area-based approaches have been applied in California mixed-conifer forests but their estimates have not been validated. To assess the accuracy and precision of plotless density estimators with potential for application to GLO data in this region, we imposed a GLO sampling scheme on six mapped forest stands of known densities (159-784 trees/ha) in the Sierra Nevada in California, USA, and Baja California Norte, Mexico. We compared three distance-based plotless density estimators (Cottam, Pollard, and Morisita) as well as two Voronoi area (VA) estimators, the Delincé and mean harmonic Voronoi density (MHVD), to the true densities. We simulated sampling schemes of increasing intensity to assess sampling error. The relative error (RE) of density estimates for the GLO sampling scheme ranged from 0.36 to 4.78. The least biased estimate of tree density in every stand was obtained with the Morisita estimator and the most biased was obtained with the MHVD estimator. The MHVD estimates of tree density were 1.2-3.8 times larger than the true densities and performed best in stands subject to fire exclusion for 100 yr. The Delincé approach obtained accurate estimates of density, implying that the Voronoi approach is theoretically sound but that its application in the MHVD was flawed. The misapplication was attributed to two causes: (1) the use of a crown scaling factor that does not correct for the number of trees sampled and (2) the persistent underestimate of the true VA due to a weak relationship between tree size and VA. The magnitude of differences between true densities and MHVD estimates suggest caution in using results based on the MHVD to inform management and restoration practices in the conifer forests of the American West.
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Affiliation(s)
- Carrie R Levine
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, Berkeley, California, 94720, USA
| | - Charles V Cogbill
- Harvard Forest, Harvard University, 324 North Main Street, Petersham, Massachusetts, 01366, USA
| | - Brandon M Collins
- University of California Center for Fire Research and Outreach, College of Natural Resources, University of California, Berkeley, California, 94720, USA
| | - Andrew J Larson
- Department of Forest Management, University of Montana, 32 Campus Drive, Missoula, Montana, 59812, USA
| | - James A Lutz
- S. J. & Jessie E. Quinney College of Natural Resources, Utah State University, 5230 Old Main Hill, Logan, Utah, 84322, USA
| | - Malcolm P North
- USDA Forest Service, Pacific Southwest Research Station, 1731 Research Park Drive, Davis, California, 95618, USA
| | - Christina M Restaino
- Department of Environmental Science and Policy, University of California, Davis, One Shields Avenue, Davis, California, 95616, USA
| | - Hugh D Safford
- Department of Environmental Science and Policy, University of California, Davis, One Shields Avenue, Davis, California, 95616, USA
- USDA Forest Service, Pacific Southwest Region, 1323 Club Drive, Vallejo, California, 94592, USA
| | - Scott L Stephens
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, Berkeley, California, 94720, USA
| | - John J Battles
- Department of Environmental Science, Policy, and Management, University of California, 130 Mulford Hall, Berkeley, California, 94720, USA
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37
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Numerical Investigation of Aggregated Fuel Spatial Pattern Impacts on Fire Behavior. LAND 2017. [DOI: 10.3390/land6020043] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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38
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O'Connor CD, Falk DA, Lynch AM, Swetnam TW, Wilcox CP. Disturbance and productivity interactions mediate stability of forest composition and structure. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:900-915. [PMID: 28029193 DOI: 10.1002/eap.1492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/06/2016] [Accepted: 12/12/2016] [Indexed: 06/06/2023]
Abstract
Fire is returning to many conifer-dominated forests where species composition and structure have been altered by fire exclusion. Ecological effects of these fires are influenced strongly by the degree of forest change during the fire-free period. Response of fire-adapted species assemblages to extended fire-free intervals is highly variable, even in communities with similar historical fire regimes. This variability in plant community response to fire exclusion is not well understood; however, ecological mechanisms such as individual species' adaptations to disturbance or competition and underlying site characteristics that facilitate or impede establishment and growth have been proposed as potential drivers of assemblage response. We used spatially explicit dendrochronological reconstruction of tree population dynamics and fire regimes to examine the influence of historical disturbance frequency (a proxy for adaptation to disturbance or competition), and potential site productivity (a proxy for underlying site characteristics) on the stability of forest composition and structure along a continuous ecological gradient of pine, dry mixed-conifer, mesic mixed-conifer, and spruce-fir forests following fire exclusion. While average structural density increased in all forests, species composition was relatively stable in the lowest productivity pine-dominated and highest productivity spruce-fir-dominated sites immediately following fire exclusion and for the next 100 years, suggesting site productivity as a primary control on species composition and structure in forests with very different historical fire regimes. Species composition was least stable on intermediate productivity sites dominated by mixed-conifer forests, shifting from primarily fire-adapted species to competition-adapted, fire-sensitive species within 20 years of fire exclusion. Rapid changes to species composition and stand densities have been interpreted by some as evidence of high-severity fire. We demonstrate that the very different ecological process of fire exclusion can produce similar changes by shifting selective pressures from disturbance-mediated to productivity-mediated controls. Restoring disturbance-adapted species composition and structure to intermediate productivity forests may help to buffer them against projected increasing temperatures, lengthening fire seasons, and more frequent and prolonged moisture stress. Fewer management options are available to promote adaptation in forest assemblages historically constrained by underlying site productivity.
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Affiliation(s)
- Christopher D O'Connor
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, 85721, USA
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona, 85721, USA
| | - Donald A Falk
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, 85721, USA
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona, 85721, USA
| | - Ann M Lynch
- U.S. Forest Service, Rocky Mountain Research Station, Tucson, Arizona, 85721, USA
| | - Thomas W Swetnam
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, Arizona, 85721, USA
| | - Craig P Wilcox
- U.S. Forest Service, Coronado National Forest, Safford, Arizona, 85546, USA
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39
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Fire and the Distribution and Uncertainty of Carbon Sequestered as Aboveground Tree Biomass in Yosemite and Sequoia & Kings Canyon National Parks. LAND 2017. [DOI: 10.3390/land6010010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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40
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Becker KML, Lutz JA. Can low‐severity fire reverse compositional change in montane forests of the Sierra Nevada, California, USA? Ecosphere 2016. [DOI: 10.1002/ecs2.1484] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Kendall M. L. Becker
- Wildland Resources DepartmentUtah State University 5230 Old Main Hill Logan Utah 84322 USA
| | - James A. Lutz
- Wildland Resources DepartmentUtah State University 5230 Old Main Hill Logan Utah 84322 USA
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41
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Odindi J, Ojoyi M, Mutanga O, Abdel-Rahman E. Analysing fragmentation in vulnerable biodiversity hotspots in Tanzania from 1975 to 2012 using remote sensing and fragstats. NATURE CONSERVATION 2016. [DOI: 10.3897/natureconservation.16.9312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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42
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Kelt DA, Sollmann R, White AM, Roberts SL, Van Vuren DH. Diversity of small mammals in the Sierra Nevada: filtering by natural selection or by anthropogenic activities? J Mammal 2016. [DOI: 10.1093/jmammal/gyw158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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43
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Stephens SL, Miller JD, Collins BM, North MP, Keane JJ, Roberts SL. Wildfire impacts on California spotted owl nesting habitat in the Sierra Nevada. Ecosphere 2016. [DOI: 10.1002/ecs2.1478] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Scott L. Stephens
- Division of Ecosystem Science Department of Environmental Science, Policy, and Management University of California 130 Mulford Hall Berkeley California 94720 USA
| | - Jay D. Miller
- USDA Forest Service Pacific Southwest Region, Fire and Aviation Management McClellan California 95652 USA
| | - Brandon M. Collins
- Pacific Southwest Research Station USDA Forest Service Davis California 95618 USA
- Center for Fire Research and Outreach University of California Berkeley California 94720 USA
| | - Malcolm P. North
- Pacific Southwest Research Station USDA Forest Service Davis California 95618 USA
| | - John J. Keane
- Pacific Southwest Research Station USDA Forest Service Davis California 95618 USA
| | - Susan L. Roberts
- University of California, Merced, Sierra Nevada Research Station 7799 Chilnualna Falls Road Wawona California 95389 USA
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44
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Johnston JD, Bailey JD, Dunn CJ. Influence of fire disturbance and biophysical heterogeneity on pre‐settlement ponderosa pine and mixed conifer forests. Ecosphere 2016. [DOI: 10.1002/ecs2.1581] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- James D. Johnston
- Oregon State UniversityCollege of Forestry 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - John D. Bailey
- Oregon State UniversityCollege of Forestry 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
| | - Christopher J. Dunn
- Oregon State UniversityCollege of Forestry 140 Peavy Hall, 3100 SW Jefferson Way Corvallis Oregon 97333 USA
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Stephens SL, Collins BM, Biber E, Fulé PZ. U.S.
federal fire and forest policy: emphasizing resilience in dry forests. Ecosphere 2016. [DOI: 10.1002/ecs2.1584] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Scott L. Stephens
- Division of Ecosystem ScienceDepartment of Environmental Science, Policy, and ManagementUniversity of California 130 Mulford Hall Berkeley California 94720 USA
| | - Brandon M. Collins
- Center for Fire Research and OutreachUniversity of California Berkeley California 94720 USA
| | - Eric Biber
- University of California, BerkeleySchool of Law 436 North Addition Berkeley California 94720 USA
| | - Peter Z. Fulé
- School of ForestryCollege of Engineering, Forestry, and Natural SciencesNorthern Arizona University Flagstaff Arizona 86011 USA
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46
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Bradley CM, Hanson CT, DellaSala DA. Does increased forest protection correspond to higher fire severity in frequent‐fire forests of the western United States? Ecosphere 2016. [DOI: 10.1002/ecs2.1492] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
| | - Chad T. Hanson
- Earth Island Institute 2150 Allston Way Suite 460 Berkeley California 94704 USA
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48
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Stevens JT, Safford HD, North MP, Fried JS, Gray AN, Brown PM, Dolanc CR, Dobrowski SZ, Falk DA, Farris CA, Franklin JF, Fulé PZ, Hagmann RK, Knapp EE, Miller JD, Smith DF, Swetnam TW, Taylor AH. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America. PLoS One 2016; 11:e0147688. [PMID: 27196621 PMCID: PMC4873010 DOI: 10.1371/journal.pone.0147688] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 12/20/2015] [Indexed: 11/30/2022] Open
Abstract
Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the “stand age” variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical “mixed-severity” fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.
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Affiliation(s)
- Jens T. Stevens
- John Muir Institute of the Environment, University of California, Davis, CA, 95616, United States of America
- * E-mail:
| | - Hugh D. Safford
- USDA Forest Service, Pacific Southwest Region, Vallejo, CA, 94592, United States of America
- Department of Environmental Science and Policy, University of California, Davis, CA, 95616, United States of America
| | - Malcolm P. North
- John Muir Institute of the Environment, University of California, Davis, CA, 95616, United States of America
- USDA Forest Service, Pacific Southwest Research Station, Davis, CA, 95616, United States of America
| | - Jeremy S. Fried
- USDA Forest Service, Forest Inventory and Analysis Program, Pacific Northwest Research Station, Portland, OR, 97205, United States of America
| | - Andrew N. Gray
- USDA Forest Service, Forest Inventory and Analysis Program, Pacific Northwest Research Station, Corvallis, OR, 97331, United States of America
| | - Peter M. Brown
- Rocky Mountain Tree-Ring Research, Fort Collins, CO, 80526, United States of America
| | - Christopher R. Dolanc
- Biology Department, Mercyhurst University, Erie, PA, 16546, United States of America
| | - Solomon Z. Dobrowski
- Dept. Forest Management, University of Montana, Missoula, MT, 59812, United States of America
| | - Donald A. Falk
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, United States of America
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, United States of America
| | - Calvin A. Farris
- National Park Service, Pacific West Region, Fire and Aviation Management, Klamath Falls, OR, 97601, United States of America
| | - Jerry F. Franklin
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, 98195, United States of America
| | - Peter Z. Fulé
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011, United States of America
| | - R. Keala Hagmann
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, 98195, United States of America
| | - Eric E. Knapp
- USDA Forest Service, Pacific Southwest Research Station, Redding, CA, 96002, United States of America
| | - Jay D. Miller
- USDA Forest Service, Pacific Southwest Region, Fire and Aviation Management, McClellan, CA, 95652, United States of America
| | - Douglas F. Smith
- Yosemite National Park, Yosemite, CA, 95389, United States of America
| | - Thomas W. Swetnam
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, United States of America
| | - Alan H. Taylor
- Department of Geography and Earth and Environmental Systems Institute, The Pennsylvania State University, University Park, PA, 16802, United States of America
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Dow CB, Collins BM, Stephens SL. Incorporating Resource Protection Constraints in an Analysis of Landscape Fuel-Treatment Effectiveness in the Northern Sierra Nevada, CA, USA. ENVIRONMENTAL MANAGEMENT 2016; 57:516-530. [PMID: 26614351 DOI: 10.1007/s00267-015-0632-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 11/17/2015] [Indexed: 06/05/2023]
Abstract
Finding novel ways to plan and implement landscape-level forest treatments that protect sensitive wildlife and other key ecosystem components, while also reducing the risk of large-scale, high-severity fires, can prove to be difficult. We examined alternative approaches to landscape-scale fuel-treatment design for the same landscape. These approaches included two different treatment scenarios generated from an optimization algorithm that reduces modeled fire spread across the landscape, one with resource-protection constrains and one without the same. We also included a treatment scenario that was the actual fuel-treatment network implemented, as well as a no-treatment scenario. For all the four scenarios, we modeled hazardous fire potential based on conditional burn probabilities, and projected fire emissions. Results demonstrate that in all the three active treatment scenarios, hazardous fire potential, fire area, and emissions were reduced by approximately 50 % relative to the untreated condition. Results depict that incorporation of constraints is more effective at reducing modeled fire outputs, possibly due to the greater aggregation of treatments, creating greater continuity of fuel-treatment blocks across the landscape. The implementation of fuel-treatment networks using different planning techniques that incorporate real-world constraints can reduce the risk of large problematic fires, allow for landscape-level heterogeneity that can provide necessary ecosystem services, create mixed forest stand structures on a landscape, and promote resilience in the uncertain future of climate change.
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Affiliation(s)
- Christopher B Dow
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA.
| | - Brandon M Collins
- USDA Forest Service, Pacific Southwest Research Station, Davis, CA, 95618, USA
- Center for Fire Research and Outreach, University of California, Berkeley, CA, 94720-3114, USA
| | - Scott L Stephens
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
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Tempel DJ, Gutiérrez RJ, Battles JJ, Fry DL, Su Y, Guo Q, Reetz MJ, Whitmore SA, Jones GM, Collins BM, Stephens SL, Kelly M, Berigan WJ, Peery MZ. Evaluating short- and long-term impacts of fuels treatments and simulated wildfire on an old-forest species. Ecosphere 2015. [DOI: 10.1890/es15-00234.1] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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