Landscape Variation In Tree Regeneration And Snag Fall Drive Fuel Loads In 24 Year Old Post Fire Lodgepole Pine Forests

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Landscape Variation in Tree Regeneration and Snag Fall Drive Fuel Loads in 24-year Old Post-fire Lodgepole Pine Forests

Author : Kellen N. Nelson
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Landscape Variation in Tree Regeneration and Snag Fall Drive Fuel Loads in 24-year Old Post-fire Lodgepole Pine Forests by : Kellen N. Nelson

Download or read book Landscape Variation in Tree Regeneration and Snag Fall Drive Fuel Loads in 24-year Old Post-fire Lodgepole Pine Forests written by Kellen N. Nelson and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Escalating wildfire in subalpine forests with stand-replacing fire regimes is increasing the extent of early-seral forests throughout the western USA. Post-fire succession generates the fuel for future fires, but little is known about fuel loads and their variability in young post-fire stands. We sampled fuel profiles in 24-year- old post-fire lodgepole pine (Pinus contorta var. latifolia) stands (n = 82) that regenerated from the 1988 Yellowstone Fires to answer three questions. (1) How do canopy and surface fuel loads vary within and among young lodgepole pine stands? (2) How do canopy and surface fuels vary with pre-and post-fire lodgepole pine stand structure and environmental conditions? (3) How have surface fuels changed between eight and 24 years post-fire? Fuel complexes varied tremendously across the landscape despite having regenerated from the same fires. Available canopy fuel loads and canopy bulk density averaged 8.5 Mg/ha (range 0.0?46.6) and 0.24 kg/m3 (range: 0.0?2.3), respectively, meeting or exceeding levels in mature lodgepole pine forests. Total surface-fuel loads averaged 123 Mg/ha (range: 43?207), and 88% was in the 1,000-h fuel class. Litter, 1-h, and 10-h surface fuel loads were lower than reported for mature lodgepole pine forests, and 1,000-h fuel loads were similar or greater. Among-plot variation was greater in canopy fuels than surface fuels, and within-plot variation was greater than among-plot variation for nearlyall fuels. Post-fire lodgepole pine density was the strongest positive predictor of canopy and fine surface fuel loads. Pre-fire successional stage was the best predictor of 100-h and 1,000-h fuel loads in the post-fire stands and strongly influenced the size and proportion of sound logs (greater when late successional stands had burned) and rotten logs (greater when early successional stands had burned). Our data suggest that 76% of the young post-fire lodgepole pine forests have 1,000-h fuel loads that exceed levels associated with high-severity surface fire potential, and 63% exceed levels associated with active crown fire potential. Fire rotations in Yellowstone National Park are predicted to shorten to a few decades and this prediction cannot be ruled out by a lack of fuels to carry repeated fires.

Forests as Complex Social and Ecological Systems

Author : Patrick J. Baker
Publisher : Springer Nature
ISBN 13 : 3030885550
Total Pages : 340 pages
Book Rating : 4.0/5 (38 download)

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Book Synopsis Forests as Complex Social and Ecological Systems by : Patrick J. Baker

Download or read book Forests as Complex Social and Ecological Systems written by Patrick J. Baker and published by Springer Nature. This book was released on 2022-05-17 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Professor Chadwick Dearing Oliver has made major intellectual contributions to forest science and natural resources management. Over the course of his career he has actively sought to bring research and practice together through synthesis, outreach, and capacity-building. A common thread throughout his career has been complexity and how we as a society understand and manage complex systems. His work on forest stand dynamics, landscape management, and sustainability have all focused on the emergent properties of complex ecological and/or social systems. This volume celebrates a remarkable career through a diverse group of former students and colleagues who work on a wide range of subject areas related to the management of complex natural resource systems. Over the past decade there has been considerable discussion about forests as complex adaptive systems. Advances in remote sensing, social methods, and data collection and processing have enabled more detailed characterisations of complex natural systems across spatial and temporal scales than ever before. Making sense of these data, however, requires conceptual frameworks that are robust to the complexity of the systems and their inherent dynamics, particularly in the context of global change. This volume presents a collection of cutting-edge research on natural ecosystems and their dynamics through the lens of complex adaptive systems. It includes contributions by a wide range of authors from academia, NGOs, forest industry, and governmental organisations with diverse perspectives on forests and natural resources management. Each chapter offers new insights into how these systems can be made more resilient to ensure that they provide a diversity of ecological and social values well into the future. Together they provide a robust way of thinking about the many challenges that natural ecosystems face and how we as society may best address them.

Requiem for America's Best Idea

Author : Michael J. Yochim
Publisher : University of New Mexico Press
ISBN 13 : 0826363431
Total Pages : 304 pages
Book Rating : 4.8/5 (263 download)

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Book Synopsis Requiem for America's Best Idea by : Michael J. Yochim

Download or read book Requiem for America's Best Idea written by Michael J. Yochim and published by University of New Mexico Press. This book was released on 2022 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: In his enthusiastic explorations and fervent writing, Michael J. Yochim "was to Yellowstone what Muir was to Yosemite. . . . Other times, his writing is like that of Edward Abbey, full of passion for the natural world and anger at those who are abusing it," writes foreword contributor William R. Lowry. In 2013 Yochim was diagnosed with ALS (Lou Gehrig's disease). While fighting the disease, he wrote Requiem for America's Best Idea. The book establishes a unique parallel between Yochim's personal struggle with a terminal illness and the impact climate change is having on the national parks--the treasured wilderness that he loved and to which he dedicated his life. Yochim explains how climate change is already impacting the vegetation, wildlife, and the natural conditions in Olympic, Grand Canyon, Glacier, Yellowstone, and Yosemite National Parks. A poignant and thought-provoking work, Requiem for America's Best Idea investigates the interactions between people and nature and the world that can inspire and destroy them.

Fire Ecology and Management: Past, Present, and Future of US Forested Ecosystems

Author : Cathryn H. Greenberg
Publisher : Springer Nature
ISBN 13 : 3030732673
Total Pages : 513 pages
Book Rating : 4.0/5 (37 download)

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Book Synopsis Fire Ecology and Management: Past, Present, and Future of US Forested Ecosystems by : Cathryn H. Greenberg

Download or read book Fire Ecology and Management: Past, Present, and Future of US Forested Ecosystems written by Cathryn H. Greenberg and published by Springer Nature. This book was released on 2021-10-01 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited volume presents original scientific research and knowledge synthesis covering the past, present, and potential future fire ecology of major US forest types, with implications for forest management in a changing climate. The editors and authors highlight broad patterns among ecoregions and forest types, as well as detailed information for individual ecoregions, for fire frequencies and severities, fire effects on tree mortality and regeneration, and levels of fire-dependency by plant and animal communities. The foreword addresses emerging ecological and fire management challenges for forests, in relation to sustainable development goals as highlighted in recent government reports. An introductory chapter highlights patterns of variation in frequencies, severities, scales, and spatial patterns of fire across ecoregions and among forested ecosystems across the US in relation to climate, fuels, topography and soils, ignition sources (lightning or anthropogenic), and vegetation. Separate chapters by respected experts delve into the fire ecology of major forest types within US ecoregions, with a focus on the level of plant and animal fire-dependency, and the role of fire in maintaining forest composition and structure. The regional chapters also include discussion of historic natural (lightning-ignited) and anthropogenic (Native American; settlers) fire regimes, current fire regimes as influenced by recent decades of fire suppression and land use history, and fire management in relation to ecosystem integrity and restoration, wildfire threat, and climate change. The summary chapter combines the major points of each chapter, in a synthesis of US-wide fire ecology and forest management into the future. This book provides current, organized, readily accessible information for the conservation community, land managers, scientists, students and educators, and others interested in how fire behavior and effects on structure and composition differ among ecoregions and forest types, and what that means for forest management today and in the future.

Drivers of Fuels, Flammability, and Fire Behavior in Young, Post-fire Lodgepole Pine Forests

Author : Kellen N. Nelson
Publisher :
ISBN 13 : 9780355093513
Total Pages : 123 pages
Book Rating : 4.0/5 (935 download)

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Book Synopsis Drivers of Fuels, Flammability, and Fire Behavior in Young, Post-fire Lodgepole Pine Forests by : Kellen N. Nelson

Download or read book Drivers of Fuels, Flammability, and Fire Behavior in Young, Post-fire Lodgepole Pine Forests written by Kellen N. Nelson and published by . This book was released on 2017 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fire and bark beetles have affected vast areas of forest over the past several decades raising concern about the risk of subsequent burning. Little is known about how fuel loads and fire behavior vary shortly after burning, nor how forest flammability might differ between stands recovering from fire and bark beetles. To address this, we investigated the variation and drivers of fuel characteristics (Chapter 2) and fire behavior (Chapter 3) in 24-year-old post-fire lodgepole pine (Pinus contorta var. latifolia) stands that regenerated after the 1988 Yellowstone Fires. To assess differences in flammability between disturbance types (Chapter 4), we intensively sampled meteorological conditions and fuel moisture content in adjacent burned and bark beetle-affected forest sites. Both sites were approximately 24 years since disturbance. Our results indicate that fuel characteristics varied tremendously across the post-1988 Yellowstone landscape and were sufficient to support fire in all stands. Total surface-fuel loads in post-disturbance forests were similar or greater than those reported in mature lodgepole pine stands; however, 88% of fuel was in the 1000-hr fuel class, and litter, 1-hr, and 10-hr surface fuel loads were lower than values reported for mature lodgepole pine forests. Pre-fire successional stage was the best predictor of 100-hr and 1000-hr fuel and strongly influenced the size and proportion of sound and rotten logs, where post-fire stand structure was the best predictor of litter, 1-hr, and 10-hr fuels. Available canopy fuel loads and canopy bulk density met or exceeded loads observed in mature lodgepole pine forests, exhibited a strong positive relationship with post-fire lodgepole pine density, and were the primary drivers of crown fire behavior. Meteorological conditions in post-fire sites exhibited symptoms of earlier snowmelt, greater evapotranspiration, and greater drought stress than post-bark beetle sites, and live fuel moisture content mimicked these differences as post-fire sites broke dormancy earlier and experienced longer, more severe drought conditions than post-bark beetle sites. Dead fuel moisture content was similar in burned and bark beetle affected sites in July, but had a greater response to heavy August precipitation that resulted in higher dead fuel moisture content on the post-burn sites. In sum, our data suggest that 76% of the young post-fire lodgepole pine forests have 1000-hr fuel loads that exceed levels associated with high-severity surface fire, and 63% exceed canopy bulk densities associated with spreading crown fire. Fire simulation modeling predicted active crown fire in 90% of stands at wind speeds >20 km hr−1, regardless of fuel moisture condition. We conclude that 24-year old lodgepole pine forests can readily support fire intervals shorter than those observed historically in Yellowstone National Park, and that dead fuel moisture content appears more dynamic while foliar fuel moisture content might be less dynamic on post-fire sites than post-bark beetle sites. Overall, the potential for crown fire is high across the post-1988 Yellowstone landscape, and post-fire sites appear to be more flammable than post-bark beetle sites during dry periods. Given a less developed canopy seed bank and a high potential for crown fire, young post-fire lodgepole pine forests are likely to have lower reproductive potential than comparable mature forests. Progressive reductions in tree recruitment after short-interval fires may lead to self-limiting dynamics where lack of fuels limit continued short-interval burning.

Stand Density and Age Affect Tree-level Structural and Functional Characteristics of Young, Postfire Lodgepole Pine in Yellowstone National Park

Download Stand Density and Age Affect Tree-level Structural and Functional Characteristics of Young, Postfire Lodgepole Pine in Yellowstone National Park PDF Online Free

Author : Paige E. Copenhaver
Publisher :
ISBN 13 :
Total Pages : 11 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Stand Density and Age Affect Tree-level Structural and Functional Characteristics of Young, Postfire Lodgepole Pine in Yellowstone National Park by : Paige E. Copenhaver

Download or read book Stand Density and Age Affect Tree-level Structural and Functional Characteristics of Young, Postfire Lodgepole Pine in Yellowstone National Park written by Paige E. Copenhaver and published by . This book was released on 2014 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: More frequent fire activity associated with climate warming is expected to increase the extent of young forest stands in fire-prone landscapes, yet growth rates and biomass allocation patterns in young forests that regenerated naturally following stand-replacing fire have not been well studied. We assessed the structural and functional characteristics of young, postfire lodgepole pine (Pinus contorta var. latifolia) trees across the Yellowstone subalpine plateaus to understand the influence of postfire stand density and age on tree-level aboveground biomass (AB), component biomass (bole, branch, foliage), partitioning to components, tree-level aboveground net primary productivity (ANPP) and leaf area (LA). Sixty 24-year-old lodgepole pine trees were harvested from 21 sites ranging from 500 to 74,667 stems?ha?1 for development of allometric equations to predict biomass, ANPP and LA. All traits increased nonlinearly with increasing tree basal diameter. Tree-level total AB and component biomass decreased with increasing stand density and increased with age when compared with measurements from 11-year-old trees. Bole partitioning increased with stand density, while foliage and branch wood partitioning declined. Tree-level ANPP and LA decreased significantly with stand density and age. Overall, our results indicate that stand density and age explain much of the variation in tree characteristics and that 24 years after fire, the initial postfire regeneration density is still exerting significant influence on the structure and function of individual trees.

Twenty-four Years After the Yellowstone Fires

Author : Monica Goigel Turner
Publisher :
ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Twenty-four Years After the Yellowstone Fires by : Monica Goigel Turner

Download or read book Twenty-four Years After the Yellowstone Fires written by Monica Goigel Turner and published by . This book was released on 2016 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Disturbance and succession have long been of interest in ecology, but how landscape patterns of ecosystem structure and function evolve following large disturbances is poorly understood. After nearly 25 years, lodgepole pine ( Pinus contorta var. latifolia) forests that regenerated after the 1988 Yellowstone Fires (Wyoming, USA) offer a prime opportunity to track the fate of disturbance-created heterogeneity in stand structure and function in a wilderness setting. In 2012, we resampled 72 permanent plots to ask (1) How have postfire stand structure and function changed between 11 and 24 yr postfire, and what variables explain these patterns and changes? (2) How has landscape-level (among-stand) variability in postfire stand structure and function changed between 11 and 24 yr postfire? We expected to see evidence of convergence beginning to emerge, but also that initial postfire stem density would still determine trajectories of biomass accumulation. After 24 yr, postfire lodgepole pine density remained very high (mean = 21,738 stems/ha, range = 0-344,067 stems/ha). Stem density increased in most plots between 11 and 24 yr postfire, but declined sharply where 11-yr-postfire stem density was >72,000 stems/ha. Stems were small in high-density stands, but stand-level lodgepole pine leaf area, foliage biomass, and live aboveground biomass increased over time and with increasing stem density. After 24 yr, mean annual lodgepole pine aboveground net primary production ( ANPP) was high (mean = 5 Mg?ha?1?yr?1, range = 0-16.5 Mg?ha?1?yr?1). Among stands, lodgepole pine ANPP increased with stem density, which explained 69% of the variation; another 8% of the variation was explained by environmental covariates. Early patterns of postfire lodgepole pine regeneration, which were contingent on prefire serotiny and fire severity, remained the dominant driver of stand structure and function. We observed mechanisms that would lead to convergence in stem density (structure) over time, but it was landscape variation in functional variables that declined substantially. Stand structure and function have not converged across the burned landscape, but our evidence suggests function will converge sooner than structure.

Effects of Timber Harvest Following Wildfire in Western North America

Author :
Publisher :
ISBN 13 :
Total Pages : 60 pages
Book Rating : 4.:/5 (319 download)

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Book Synopsis Effects of Timber Harvest Following Wildfire in Western North America by :

Download or read book Effects of Timber Harvest Following Wildfire in Western North America written by and published by . This book was released on 2009 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: This synthesis provides an ecological foundation for management of the diverse ecosystems and fire regimes of North America, based on scientific principles of fire interactions with vegetation, fuels, and biophysical processes. Although a large amount of scientific data on fire exists, most of those data have been collected at small spatial and temporal scales. Thus, it is challenging to develop consistent science-based plans for large spatial and temporal scales where most fire management and planning occur. Understanding the regional geographic context of fire regimes is critical for developing appropriate and sustainable management strategies and policy. The degree to which human intervention has modified fire frequency, intensity, and severity varies greatly among different ecosystems, and must be considered when planning to alter fuel loads or implement restorative treatments. Detailed discussion of six ecosystems--ponderosa pine forest (western North America), chaparral (California), boreal forest (Alaska and Canada), Great Basin sagebrush (intermountain West), pine and pine-hardwood forests (Southern Appalachian Mountains), and longleaf pine (Southeastern United States)--illustrates the complexity of fire regimes and that fire management requires a clear regional focus that recognizes where conflicts might exist between fire hazard reduction and resource needs. In some systems, such as ponderosa pine, treatments are usually compatible with both fuel reduction and resource needs, whereas in others, such as chaparral, the potential exists for conflicts that need to be closely evaluated. Managing fire regimes in a changing climate and social environment requires a strong scientific basis for developing fire management and policy. --

Effects of Timber Harvest Following Wildfire in Western North America

Author : David L. Peterson
Publisher : DIANE Publishing
ISBN 13 : 1437926665
Total Pages : 60 pages
Book Rating : 4.4/5 (379 download)

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Book Synopsis Effects of Timber Harvest Following Wildfire in Western North America by : David L. Peterson

Download or read book Effects of Timber Harvest Following Wildfire in Western North America written by David L. Peterson and published by DIANE Publishing. This book was released on 2010-11 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Timber harvest following wildfire leads to different outcomes depending on the biophysical setting of the forest, pattern of burn severity, operational aspects of tree removal, and other activities. Postfire logging adds to these effects by removing standing dead trees (snags) and disturbing the soil. The influence of postfire logging depends on the intensity of the fire, intensity of the logging operation, and mgmt. activities such as fuel treatments. Removal of snags reduces long-term fuel loads but generally results in increased amounts of fine fuels for the first few years after logging. Cavity-nesting birds, small mammals, and amphibians may be affected by harvest of standing dead and live trees, with negative effects on most species. Illustrations.

Wildland Fire in Ecosystems

Author :
Publisher :
ISBN 13 :
Total Pages : 92 pages
Book Rating : 4.3/5 (243 download)

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Book Synopsis Wildland Fire in Ecosystems by :

Download or read book Wildland Fire in Ecosystems written by and published by . This book was released on 1998 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Post-fire Forest Recovery and Restoration in a Changing Climate

Author : Derek Jon Nies Young
Publisher :
ISBN 13 : 9780355969122
Total Pages : pages
Book Rating : 4.9/5 (691 download)

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Book Synopsis Post-fire Forest Recovery and Restoration in a Changing Climate by : Derek Jon Nies Young

Download or read book Post-fire Forest Recovery and Restoration in a Changing Climate written by Derek Jon Nies Young and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Yellow pine and mixed-conifer (YPMC) forests in California are subject to multiple anthropogenic pressures, including fire suppression and climate change. Although YPMC forests historically experienced a high-frequency, low-severity fire regime, fire suppression has resulted in increased fuel loads and has therefore increased the severity of the fires that do occur. Some of the historically dominant tree species in YPMC forests, particularly pines (Pinus spp.), establish primarily following wildfire. However, the increasing extent of severely-burned areas with few nearby seed sources for conifer regeneration has resulted in poor post-fire tree recruitment across large areas. Climate change has the potential to further substantially alter post-fire regeneration patterns. When post-fire tree regeneration is poor, managers often plant tree seedlings in order to speed forest recovery. However, little is known about (a) how natural post-fire tree regeneration patterns may change as climate changes and (b) how appropriate seed sources for post-fire tree seedling plantings should be selected. Further, despite the fact that most studies of climate change impacts rely on modeled climate variables when examining the relationship between climate and vegetation, there has been little critical evaluation of several important climate variables that are increasingly used in ecological analyses. I address these knowledge gaps in this dissertation. In Chapter 1, I evaluate some central assumptions that are made when modeling climatic water balance variables including actual evapotranspiration (AET) and climatic water deficit (CWD). I find that the assumptions can substantially affect both the absolute and relative values of modeled AET and CWD across landscapes—as well as the inferences drawn from ecological analyses that apply the variables—despite the fact that there is no practical means for avoiding the need to make assumptions. Representing the hydrological climate using simple precipitation variables may introduce less bias than using AET and CWD. In Chapter 2, I use recent interannual variation in precipitation to evaluate the sensitivity of post-fire tree recruitment to changes in precipitation patterns. I find that while post-fire recruitment of some conifer species is reduced—and recruitment of shrubs increased—under post-fire drought, the response of post-fire tree seedling species composition to weather variation is constrained by the species composition of the surrounding unburned forest. Forest tree community composition thus may not rapidly shift as climate changes. Finally, in Chapter 3, I test the application of assisted gene flow—the managed relocation of genotypes within the species’ range—in large-scale post-fire restoration plantings. I find that in the short term, under anomalously hot and dry conditions, trees grown from seed collected at elevations below the planting site generally perform as well as, if not significantly better than, trees grown from seed collected near the planting site. However, challenges specific to large-scale restoration projects—in particular, the use of seed collections that are not geographically precise—can complicate selection of appropriate provenances and lead to unexpected results. Overall, the work in this dissertation contributes to increased potential to understand and predict the natural response of forest ecosystems to climate change and to update management practices in response to changes in climate.

The Colorado Front Range

Author : Thomas T. Veblen
Publisher :
ISBN 13 :
Total Pages : 204 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis The Colorado Front Range by : Thomas T. Veblen

Download or read book The Colorado Front Range written by Thomas T. Veblen and published by . This book was released on 1991 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Coarse Woody Detritus Dynamics, Variable Decay Rates and Their Contribution to Wildland Fuel Succession Following High-severity Fire Disturbance in Dry-mixed Conifer Forests of Oregon's Eastern Cascades

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Author : Christopher J. Dunn
Publisher :
ISBN 13 :
Total Pages : 140 pages
Book Rating : 4.:/5 (695 download)

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Book Synopsis Coarse Woody Detritus Dynamics, Variable Decay Rates and Their Contribution to Wildland Fuel Succession Following High-severity Fire Disturbance in Dry-mixed Conifer Forests of Oregon's Eastern Cascades by : Christopher J. Dunn

Download or read book Coarse Woody Detritus Dynamics, Variable Decay Rates and Their Contribution to Wildland Fuel Succession Following High-severity Fire Disturbance in Dry-mixed Conifer Forests of Oregon's Eastern Cascades written by Christopher J. Dunn and published by . This book was released on 2011 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing future fire severity is a proposed ecological benefit of salvage logging following wildfire disturbance. Considerable debate continues over the ability of such management practices to achieve this objective given limited understanding of coarse woody detritus (CWD) dynamics, fuel bed alterations, and post-fire vegetative growth. The objective of this study was to estimate the dynamics of snags and logs in conjunction with surface fuel accumulation following high-severity fire disturbance in dry-mixed conifer forests of Oregon's eastern Cascades. Snag dynamics (fall and breakage rates) were estimated for Abies sp., Pinus ponderosa and Pinus contorta in three DBH classes of 23 cm (small), 23-41 cm (medium) and41 cm (large). A total of 5,103 snags in thirty 0.25-ha plots were sampled at seven different fire sites, covering a 24 year chronosequence following high-severity fire disturbance. Pinus ponderosa and Pinus contorta snags had the quickest fall rates with estimated half-lives of 7-8 and 12-13 years for small and medium sized snags, respectively. Large Pinus ponderosa snags had an estimated half-life of 17-18 years. Abies sp. snags fall rates were slower, with half-life estimates of 8-9, 14-15 and 20-21 years for small, medium and large snags respectively. Breakage rates were variable but correlated with wood strength, crown and stem weight and crown position (exposure to wind). Decomposition loss rate-constants were obtained from the same fire sites, up to seven years post-fire, by removing three cross-sections from each of sixty fire-killed Abies sp. snags, sixty Pinus ponderosa snags, and forty Pinus ponderosa logs. Abies sp. snags exhibited significant decay with an estimated decomposition loss rate-constant of k = 0.0149 yr−1. Pinus ponderosa snags did not exhibit significant decay, but logs did. Sapwood and heartwood decomposition loss rate-constants equaled k = 0.0362 yr−1 and k = 0.0164 yr−1, respectively. These values confirm hypothesized differences in decay rates among species and between snags and logs in dry forest environments. An empirical model was developed to link snag fall and breakage with snag and log decomposition during succession in order to estimate the contribution of fire killed biological legacies to fine and coarse woody detritus accumulation. Legacy CWD is responsible for the largest total accumulation of surface fuel as snags break and fall, but primarily in 100- and 1000-hr fuel classes. Decomposition rates increase as CWD moves from standing to downed material, reducing total CWD biomass by 30-50% in 24 years. Fine fuels are primarily derived from post-fire vegetation and steadily increase over the 24-year period. Herbaceous fuel loads peak within 2-4 years but decrease rapidly as Ceanothus velutinus and Arctostaphylos patula shrubs establish quickly and steadily increase in total biomass over 24 years. Spread rates and flame lengths in post-fire environments are primarily driven by fuels generated from new growth. The dynamic process of snag fall and breakage, and decomposition of snags and logs, limits CWD's effect on fire spread and intensity if reburning occurs, although soil heating and total heat release can be exacerbated by the combustion of decayed logs. Salvage logging significantly reduces CWD fuels but has limited impacts on other fuel bed components. Results of this study suggest post-fire management decisions consider vegetation dynamics as well as dead wood dynamics if reducing fire hazard is a primary objective.

It Takes a Few to Tango: Changing Climate and Fire Regimes Can Cause Regeneration Failure of Two Subalpine Conifers

Author : Winslow D. Hansen
Publisher :
ISBN 13 :
Total Pages : 12 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis It Takes a Few to Tango: Changing Climate and Fire Regimes Can Cause Regeneration Failure of Two Subalpine Conifers by : Winslow D. Hansen

Download or read book It Takes a Few to Tango: Changing Climate and Fire Regimes Can Cause Regeneration Failure of Two Subalpine Conifers written by Winslow D. Hansen and published by . This book was released on 2018 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental change is accelerating in the 21st century, but how multiple drivers may interact to alter forest resilience remains uncertain. In forests affected by large high-severity disturbances, tree regeneration is a resilience linchpin that shapes successional trajectories for decades. We modeled stands of two widespread western U.S. conifers, Douglas-fir (Pseudotsuga menziesii var. glauca), and lodgepole pine (Pinus contorta var. latifolia), in Yellowstone National Park (Wyoming, USA) to ask (1) What combinations of distance to seed source, fire return interval, and warming-drying conditions cause postfire tree-regeneration failure? (2) If postfire tree regeneration was successful, how does early tree density differ under future climate relative to historical climate? We conducted a stand-level (1 ha) factorial simulation experiment using the individual-based forest process model iLand to identify combinations of fire return interval (11?100 yr), distance to seed source (50?1,000 m), and climate (historical, mid-21st century, late-21st century) where trees failed to regenerate by 30-yr postfire. If regeneration was successful, we compared stand densities between climate periods. Simulated postfire regeneration were surprisingly resilient to changing climate and fire drivers. Douglas-fir regeneration failed more frequently (55%) than lodgepole pine (28% and 16% for nonserotinous and serotinous stands, respectively). Distance to seed source was an important driver of regeneration failure for Douglas-fir and non-serotinous lodgepole pine; regeneration never failed when stands were 50 m from a seed source and nearly always failed when stands were 1 km away. Regeneration of serotinous lodgepole pine only failed when fire return intervals were ?20 yr and stands were far (1 km) from a seed source. Warming climate increased regeneration success for Douglas-fir but did not affect lodgepole pine. If regeneration was successful, postfire density varied with climate. Douglasfir and serotinous lodgepole pine regeneration density both increased under 21st-century climate but in response to different climate variables (growing season length vs. cold limitation). Results suggest that, given a warmer future with larger and more frequent fires, a greater number of stands that fail to regenerate after fires combined with increasing density in stands where regeneration is successful could produce a more coarse-grained forest landscape.

Mitigating Old Tree Mortality in Long-Unburned, Fire-Dependent Forests

Author : Sharon M. Hood
Publisher : CreateSpace
ISBN 13 : 9781480173965
Total Pages : 78 pages
Book Rating : 4.1/5 (739 download)

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Book Synopsis Mitigating Old Tree Mortality in Long-Unburned, Fire-Dependent Forests by : Sharon M. Hood

Download or read book Mitigating Old Tree Mortality in Long-Unburned, Fire-Dependent Forests written by Sharon M. Hood and published by CreateSpace. This book was released on 2012-10 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: Historically, many forested ecosystems in the United States burned frequently, both from lightning ignited fires and from Native American burning. Frequent fire maintained low fuel loadings and shaped forests composed of tree species adapted to survive low-intensity frequent fire. In the early 1900s, the United States government initiated a program to suppress all fires, both natural and anthropogenic. Many unintended consequences have resulted from over a century of fire suppression, such as increased tree densities and fuel, increased stress on older trees from competition, and greater risk of bark beetle attacks. These consequences are especially apparent in forests that historically burned frequently and have thus missed many fire cycles. Maintaining old trees and perpetuating large-diameter trees is an increasing concern. Stands of old trees that were historically common across vast landscapes in the United States are now relatively rare on the landscape because of harvesting (Noss and others 1995). Though logging is no longer the principal threat to most old-growth forests, they now face other risks (Vosick and others 2007). Prescribed fire has become a major tool for restoring fire-dependent ecosystem health and sustainability throughout the United States and use will likely increase in the future. However, increased mortality of large-diameter and old trees following fire has been reported in many areas around the country, and there is increased concern about maintaining these on the landscape (Kolb and others 2007; Varner and others 2005). As early as 1960, Ferguson and others (1960) reported high longleaf pine mortality after a low-intensity prescribed burn consumed the majority of heavy duff accumulations around the base of the trees. Mortality of pre-settlement ponderosa pines in prescribed burn areas in Grand Canyon National Park was higher than in control plots (Kaufmann and Covington 2001). After beginning a forest restoration program that reintroduced fire by prescribed burning at Crater Lake National Park, excessive post-fire mortality of larger ponderosa pine was observed in the burn areas, and early season burns had an even higher mortality than late season burns (Swezy and Agee 1991). Both Swezy and Agee (1991) and McHugh and Kolb (2003) reported a U-shaped mortality distribution for ponderosa pine following wildfires, with smaller- and larger-diameter trees having higher mortality than mid-diameter trees. Forest managers around the country have expressed concerns about large-diameter and old tree mortality when prescribed burning in long-unburned forests. The synthesis herein suggests recommendations for maintaining and perpetuating old trees in fire-dependent ecosystems. It expands on efforts funded by the Joint Fire Science Program (JFSP) to define the issues surrounding burning in fire excluded forests of the United States that are adapted to survive frequent fire. When the JFSP initially funded this synthesis, two JFSP projects were examining the effect of raking on reducing old ponderosa and Jeffrey pine (subsequently published in Fowler and others 2010; Hood and others 2007a). Another JFSP project examined the effect of prescribed burning under different duff moisture conditions on long-unburned old longleaf pine mortality (Varner and others 2007). Two other syntheses were also recently published on this subject: Perpetuating old ponderosa pine (Kolb and others 2007) and The conservation and restoration of old growth in frequent-fire forests of the American West (Egan 2007). The scope of the synthesis herein focuses only on limiting over story tree mortality in species adapted to survive frequent fire; therefore, the implications of fire suppression and fuel treatments on other ecosystem components are not discussed.

Modeling the Effects of Fire and Climate Change on Carbon and Nitrogen Storage in Lodgepole Pine (Pinus Contorta) Stands

Author : Erica A. H. Smithwick
Publisher :
ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Modeling the Effects of Fire and Climate Change on Carbon and Nitrogen Storage in Lodgepole Pine (Pinus Contorta) Stands by : Erica A. H. Smithwick

Download or read book Modeling the Effects of Fire and Climate Change on Carbon and Nitrogen Storage in Lodgepole Pine (Pinus Contorta) Stands written by Erica A. H. Smithwick and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interaction between disturbance and climate change and resultant effects on ecosystem carbon (C) and nitrogen (N) fluxes are poorly understood. Here, we model (using CENTURY version 4.5) how climate change may affect C and N fluxes among mature and regenerating lodgepole pine (Pinus contorta var. latifolia Engelm. ex S.Wats.) stands that vary in postfire tree density following stand-replacing fire. Both young (postfire) and mature stands had elevated forest production and net N mineralization under future climate scenarios relative to current climate. Forest production increased 25% [Hadley (HAD)] to 36% [Canadian Climate Center (CCC)], compared with 2% under current climate, among stands that varied in stand age and postfire density. Net N mineralization increased under both climate scenarios, e.g., 119% to 37% (HAD) and 111% to 23% (CCC), with greatest increases for young stands with sparse tree regeneration. By 2100, total ecosystem carbon (live1dead1soils) in mature stands was higher than prefire levels, e.g., 116% to 19% (HAD) and 124% to 28% (CCC). For stands regenerating following fire in 1988, total C storage was 0-9% higher under the CCC climate model, but 5-6% lower under the HAD model and 20-37% lower under the Control. These patterns, which reflect variation in stand age, postfire tree density, and climate model, suggest that although there were strong positive responses of lodgepole pine productivity to future changes in climate, C flux over the next century will reflect complex relationships between climate, age structure, and disturbance-recovery patterns of the landscape.

Natural Tree Regeneration and Coarse Woody Debris Dynamics After a Forest Fire in the Western Cascade Range

Author : Martin John Brown
Publisher :
ISBN 13 :
Total Pages : 50 pages
Book Rating : 4.:/5 (21 download)

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Book Synopsis Natural Tree Regeneration and Coarse Woody Debris Dynamics After a Forest Fire in the Western Cascade Range by : Martin John Brown

Download or read book Natural Tree Regeneration and Coarse Woody Debris Dynamics After a Forest Fire in the Western Cascade Range written by Martin John Brown and published by . This book was released on 2013 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: We monitored coarse woody debris dynamics and natural tree regeneration over a 14-year period after the 1991 Warner Creek Fire, a 3631-ha (8,972-ac) mixed severity fire in the western Cascade Range of Oregon. Rates for tree mortality in the fire, postfire mortality, snag fall, and snag fragmentation all showed distinct patterns by tree diameter and species, with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) more likely to survive a fire, and to remain standing as a snag, than other common tree species. Natural seedling regeneration was abundant, rapid, and highly variable in space. Densities of seedlings >10 cm height at 14 years postfire ranged from 1,530 to 392,000 per ha. Seedling establishment was not concentrated in a single year, and did not appear to be limited by the abundant growth of shrubs. The simultaneous processes of mortality, snag fall, and tree regeneration increased the variety of many measures of forest structure. The singular event of the fire has increased the structural diversity of the landscape.