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Ritter SM, Hoffman CM, Battaglia MA, Jain TB. Restoration and fuel hazard reduction result in equivalent reductions in crown fire behavior in dry conifer forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2682. [PMID: 35592904 PMCID: PMC9787879 DOI: 10.1002/eap.2682] [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: 09/02/2021] [Revised: 01/31/2022] [Accepted: 03/18/2022] [Indexed: 06/15/2023]
Abstract
Over the past several decades, the management of historically frequent-fire forests in the western United States has received significant attention due to the linked ecological and social risks posed by the increased occurrence of large, contiguous patches of high-severity fire. As a result, efforts are underway to simultaneously reduce potential fire and fuel hazards and restore characteristics indicative of historical forest structures and ecological processes that enhance the diversity and quality of wildlife habitat across landscapes. Despite widespread agreement on the need for action, there is a perceived tension among scientists concerning silvicultural treatments that modify stands to optimally reduce potential fire behavior (fuel hazard reduction) versus those that aim to emulate historical forest structures and create structurally complex stands (restoration). In this work, we evaluated thinning treatments in the Black Hills National Forest that exemplify the extremes of a treatment continuum that ranges from fuel hazard reduction to restoration. The goal of this work was to understand how the differing three-dimensional stand structures created by these treatment approaches altered potential fire behavior. Our results indicate that restoration treatments created higher levels of vertical and horizontal structural complexity than the fuel hazard reduction treatments but resulted in similar reductions to potential crown fire behavior. There were some trade-offs identified as the restoration treatments created larger openings, which generated faster mean rates of fire spread; however, these increased spread rates did not translate to higher levels of canopy consumption. Overall, our results suggest that treatments can create vertical and horizontal complexity desired for restoration and wildlife habitat management while reducing fire hazard and that they can be used in concert with traditional fuel hazard reduction treatments to reduce landscape scale fire risk. We also provide some suggestions to land managers seeking to design and implement prescriptions that emulate historical structures and enhance forest complexity.
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Affiliation(s)
- Scott M. Ritter
- Colorado Forest Restoration Institute, Department of Forest and Rangeland Stewardship, Warner College of Natural ResourcesColorado State UniversityFort CollinsColoradoUSA
| | - Chad M. Hoffman
- Department of Forest and Rangeland Stewardship, Warner College of Natural ResourcesColorado State UniversityFort CollinsColoradoUSA
| | - Mike A. Battaglia
- USDA Forest ServiceRocky Mountain Research StationFort CollinsColoradoUSA
| | - Theresa B. Jain
- USDA Forest ServiceRocky Mountain Research StationMoscowIdahoUSA
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Latif QS, Cannon JB, Chabot EJ, Sparks RA. Simulated treatment effects on bird communities inform landscape-scale dry conifer forest management. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2555. [PMID: 35112748 PMCID: PMC9285579 DOI: 10.1002/eap.2555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/27/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
Human land use and climate change have increased forest density and wildfire risk in dry conifer forests of western North America, threatening various ecosystem services, including habitat for wildlife. Government policy supports active management to restore historical structure and ecological function. Information on potential contributions of restoration to wildlife habitat can allow assessment of tradeoffs with other ecological benefits when prioritizing treatments. We predicted avian responses to simulated treatments representing alternative scenarios to inform landscape-scale forest management planning along the Colorado Front Range. We used data from the Integrated Monitoring in Bird Conservation Regions program to inform a hierarchical multispecies occupancy model relating species occupancy and richness with canopy cover at two spatial scales. We then simulated changes in canopy cover (remotely sensed in 2018) under three alternative scenarios, (1) a "fuels reduction" scenario representing landscape-wide 30% reduction in canopy cover, (2) a "restoration" scenario representing more nuanced, spatially variable treatments targeting historical conditions, and (3) a reference, no-change scenario. Model predictions showed areas of potential gains and losses for species richness, richness of ponderosa pine forest habitat specialists, and the ratio of specialists to generalists at two (1 km2 and 250 m2 ) spatial scales. Under both fuels reduction and restoration scenarios, we projected greater gains than losses for species richness. Surprisingly, despite restoration more explicitly targeting ecologically relevant historical conditions, fuels reduction benefited bird species richness over a greater spatial extent than restoration, particularly in the lower montane life zone. These benefits reflected generally positive species associations with moderate canopy cover promoted more consistently under the fuels reduction scenario. In practice, contemporary forest management is likely to lie somewhere between the fuels reduction and restoration scenarios represented here. Therefore, our results inform where and how active forest management can best support avian diversity. Although our study raises questions regarding the value of including landscape-scale heterogeneity as a management objective, we do not question the value of targeting finer scale heterogeneity (i.e., stand and treatment level). Rather, our results combined with those from previous work clarify the scale at which targeting structural heterogeneity and historical reference conditions can promote particular ecosystem services.
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Donovan VM, Roberts CP, Fogarty DT, Wedin DA, Twidwell D. Targeted grazing and mechanical thinning enhance forest stand resilience under a narrow range of wildfire scenarios. Ecosphere 2022. [DOI: 10.1002/ecs2.4061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Victoria M. Donovan
- Department of Agronomy and Horticulture University of Nebraska‐Lincoln Lincoln Nebraska USA
| | - Caleb P. Roberts
- Department of Agronomy and Horticulture University of Nebraska‐Lincoln Lincoln Nebraska USA
| | - Dillon T. Fogarty
- Department of Agronomy and Horticulture University of Nebraska‐Lincoln Lincoln Nebraska USA
| | - David A. Wedin
- School of Natural Resources University of Nebraska‐Lincoln Lincoln Nebraska USA
| | - Dirac Twidwell
- Department of Agronomy and Horticulture University of Nebraska‐Lincoln Lincoln Nebraska USA
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Cannon JB, Warnick KJ, Elliott S, Briggs JS. Low- and moderate-severity fire offers key insights for landscape restoration in ponderosa pine forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2490. [PMID: 34753222 DOI: 10.1002/eap.2490] [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: 02/11/2021] [Revised: 04/03/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
Restoration goals in fire-prone conifer forests include mitigating fire hazard while restoring forest structural components linked to disturbance resilience and ecological function. Restoration of overstory spatial pattern in forests often falls short of management objectives due to complexities in implementation, regulation, and available data. When historical data is available, it is often collected at plots too small to inform coarse-scale metrics like gap size and structure of tree patches (e.g., 1 ha). Principles of ecological forestry typically emphasize overstory removal patterns that emulate those of natural disturbances. So, low- and moderate-severity portions of contemporary wildfires may serve as a guide to restoration treatments where mixed-severity fires occur. Here, we compare forest spatial pattern and configuration in 15 mechanical restoration treatments and low- and moderate-severity portions of three wildfires in ponderosa pine-dominated forests to determine how they differ in spatial pattern. We obtained satellite imagery of restoration treatments and wildfires and used supervised classification to differentiate canopy and openings. We assessed elements of landscape structure including canopy and gap cover, gap attributes, and landscape heterogeneity for each disturbance type. We found that both mechanical restoration treatments and low- and moderate-severity portions of wildfires reduced forest cover, increased gap cover, and altered pattern and arrangement of gaps relative to undisturbed areas, though the magnitude of changes were greatest in the burned sites. Low- and moderate-severity wildfire consistently increased landscape heterogeneity, but mechanical treatments did not. This suggests that a greater emphasis on increasing gap and patch spatial structure may make mechanical treatments more congruent with natural disturbances. Outcomes of low- and moderate-severity portions of wildfires may provide important information upon which to base management prescriptions where reference data on landscape patterns is unavailable.
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Affiliation(s)
- Jeffery B Cannon
- The Jones Center at Ichauway, 3988 Jones Center Drive, Newton, Georgia, 39870, USA
| | - Katarina J Warnick
- Department of Forest and Rangeland Stewardship, Colorado Forest Restoration Institute, Colorado State University, 1472 Campus Delivery, Fort Collins, Colorado, 80523, USA
| | - Spencer Elliott
- Department of Forest and Rangeland Stewardship, Colorado Forest Restoration Institute, Colorado State University, 1472 Campus Delivery, Fort Collins, Colorado, 80523, USA
| | - Jennifer S Briggs
- Office of Graduate Studies, Colorado School of Mines, 1500 Illinois Street, Golden, Colorado, 80401, USA
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Prichard SJ, Hessburg PF, Hagmann RK, Povak NA, Dobrowski SZ, Hurteau MD, Kane VR, Keane RE, Kobziar LN, Kolden CA, North M, Parks SA, Safford HD, Stevens JT, Yocom LL, Churchill DJ, Gray RW, Huffman DW, Lake FK, Khatri‐Chhetri P. Adapting western North American forests to climate change and wildfires: 10 common questions. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02433. [PMID: 34339088 PMCID: PMC9285930 DOI: 10.1002/eap.2433] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 05/22/2023]
Abstract
We review science-based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes. As part of the review, we address common questions associated with climate adaptation and realignment treatments that run counter to a broad consensus in the literature. These include the following: (1) Are the effects of fire exclusion overstated? If so, are treatments unwarranted and even counterproductive? (2) Is forest thinning alone sufficient to mitigate wildfire hazard? (3) Can forest thinning and prescribed burning solve the problem? (4) Should active forest management, including forest thinning, be concentrated in the wildland urban interface (WUI)? (5) Can wildfires on their own do the work of fuel treatments? (6) Is the primary objective of fuel reduction treatments to assist in future firefighting response and containment? (7) Do fuel treatments work under extreme fire weather? (8) Is the scale of the problem too great? Can we ever catch up? (9) Will planting more trees mitigate climate change in wNA forests? And (10) is post-fire management needed or even ecologically justified? Based on our review of the scientific evidence, a range of proactive management actions are justified and necessary to keep pace with changing climatic and wildfire regimes and declining forest heterogeneity after severe wildfires. Science-based adaptation options include the use of managed wildfire, prescribed burning, and coupled mechanical thinning and prescribed burning as is consistent with land management allocations and forest conditions. Although some current models of fire management in wNA are averse to short-term risks and uncertainties, the long-term environmental, social, and cultural consequences of wildfire management primarily grounded in fire suppression are well documented, highlighting an urgency to invest in intentional forest management and restoration of active fire regimes.
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Affiliation(s)
- Susan J. Prichard
- University of Washington School of Environmental and Forest SciencesSeattleWashington98195‐2100USA
| | - Paul F. Hessburg
- University of Washington School of Environmental and Forest SciencesSeattleWashington98195‐2100USA
- U.S. Forest Service PNW Research StationWenatcheeWashington98801USA
| | - R. Keala Hagmann
- University of Washington School of Environmental and Forest SciencesSeattleWashington98195‐2100USA
- Applegate Forestry LLCCorvallisOregon97330USA
| | - Nicholas A. Povak
- U.S. Forest ServicePacific Southwest Research StationInstitute of Forest Genetics2480 Carson RoadPlacervilleCalifornia95667USA
| | - Solomon Z. Dobrowski
- University of Montana College of Forestry and ConservationMissoulaMontana59812USA
| | - Matthew D. Hurteau
- University of New Mexico Biology DepartmentAlbuquerqueNew Mexico87131‐0001USA
| | - Van R. Kane
- University of Washington School of Environmental and Forest SciencesSeattleWashington98195‐2100USA
| | - Robert E. Keane
- U.S. Forest Service Rocky Mountain Research StationMissoula Fire Sciences LaboratoryMissoulaMontana59808USA
| | - Leda N. Kobziar
- Department of Natural Resources and SocietyUniversity of IdahoMoscowIdaho83844USA
| | - Crystal A. Kolden
- School of EngineeringUniversity of California MercedMercedCalifornia95343USA
| | - Malcolm North
- U.S. Forest Service Pacific Southwest Research Station1731 Research ParkDavisCalifornia95618USA
| | - Sean A. Parks
- U.S. Forest Service Aldo Leopold Wilderness Research InstituteMissoulaMontana59801USA
| | - Hugh D. Safford
- U.S. Forest Service Pacific Southwest Research StationAlbanyCalifornia94710USA
| | - Jens T. Stevens
- U.S. Geological Survey Fort Collins Science CenterNew Mexico Landscapes Field StationSanta FeNew Mexico87544USA
| | - Larissa L. Yocom
- Department of Wildland Resources and Ecology CenterUtah State University College of Agriculture and Applied SciencesLoganUtah84322USA
| | - Derek J. Churchill
- Washington State Department of Natural Resources Forest Health ProgramOlympiaWashington98504USA
| | - Robert W. Gray
- R.W. Gray ConsultingChilliwackBritish ColumbiaV2R2N2Canada
| | - David W. Huffman
- Northern Arizona University Ecological Restoration InstituteFlagstaffArizona86011USA
| | - Frank K. Lake
- U.S. Forest Service Pacific Southwest Research StationArcataCalifornia95521USA
| | - Pratima Khatri‐Chhetri
- University of Washington School of Environmental and Forest SciencesSeattleWashington98195‐2100USA
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Ziegler JP, Hoffman CM, Collins BM, Knapp EE, Mell W(R. Pyric tree spatial patterning interactions in historical and contemporary mixed conifer forests, California, USA. Ecol Evol 2021; 11:820-834. [PMID: 33520169 PMCID: PMC7820164 DOI: 10.1002/ece3.7084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/23/2020] [Accepted: 11/12/2020] [Indexed: 11/30/2022] Open
Abstract
Tree spatial patterns in dry coniferous forests of the western United States, and analogous ecosystems globally, were historically aggregated, comprising a mixture of single trees and groups of trees. Modern forests, in contrast, are generally more homogeneous and overstocked than their historical counterparts. As these modern forests lack regular fire, pattern formation and maintenance is generally attributed to fire. Accordingly, fires in modern forests may not yield historically analogous patterns. However, direct observations on how selective tree mortality among pre-existing forest structure shapes tree spatial patterns is limited. In this study, we (a) simulated fires in historical and contemporary counterpart plots in a Sierra Nevadan mixed-conifer forest, (b) estimated tree mortality, and (c) examined tree spatial patterns of live trees before and after fire, and of fire-killed trees. Tree mortality in the historical period was clustered and density-dependent, because trees were aggregated and segregated by tree size before fire. Thus, fires maintained an aggregated distribution of tree groups. Tree mortality in the contemporary period was widespread, except for dispersed large trees, because most trees were a part of large, interconnected tree groups. Thus, postfire tree patterns were more uniform and devoid of moderately sized tree groups. Postfire tree patterns in the historical period, unlike the contemporary period, were within the historical range of variability identified for the western United States. This divergence suggests that decades of forest dynamics without significant disturbances have altered the historical means of pyric pattern formation. Our results suggest that ecological silvicultural treatments, such as forest restoration thinnings, which emulate qualities of historical forests may facilitate the reintroduction of fire as a means to reinforce forest structural heterogeneity.
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Affiliation(s)
- Justin P. Ziegler
- Department of Forest & Rangeland StewardshipColorado State UniversityFort CollinsCOUSA
| | - Chad M. Hoffman
- Department of Forest & Rangeland StewardshipColorado State UniversityFort CollinsCOUSA
| | - Brandon M. Collins
- Center for Fire Research & OutreachUniversity of CaliforniaBerkeleyCAUSA
- Pacific Southwest Research StationUS Forest ServiceDavisCAUSA
| | - Eric E. Knapp
- Pacific Southwest Research StationUS Forest ServiceReddingCAUSA
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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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