24 resources found

This paper investigates the effectiveness of various fire management treatments on western U. S. coniferous forests, which have become more susceptible to severe wildfires due to a century of fire exclusion and altered land use. Researchers analyzed the impacts of mechanical thinning, prescribed burning, and a combination of both across six diverse sites. The study found that mechanical thinning combined with prescribed fire was the most effective strategy for significantly reducing surface fuel loads, decreasing the likelihood of severe crown fires, and lowering predicted tree mortality. While mechanical-only treatments were less consistent, they were effective when whole-tree harvesting systems were used, minimizing residual surface fuels.

This document serves as a comprehensive guide for land managers considering mastication as a vegetation management tool. It synthesizes current scientific knowledge, detailing the characteristics and costs of various mastication equipment, including carrier machines and cutting heads. The report also summarizes the ecological effects of mastication on vegetation, soils, and wildlife habitat, noting the variability of these impacts across different ecosystems. It provides decision trees and implementation criteria to aid managers in selecting the most appropriate treatment methods and mastication configurations based on their specific site conditions and management objectives.

This report addresses the critical issue of maintaining large, old trees in United States forests that historically experienced frequent fires but have been subjected to long periods of fire suppression. The document synthesizes existing research to understand how reintroducing fire through prescribed burning impacts these venerable trees, particularly concerning injury and mortality. It delves into the causes of tree death from fire, including heat damage to crowns, cambium, and roots, with a specific focus on the role of accumulated duff and subsequent bark beetle attacks. Furthermore, the report examines management options and treatment effects aimed at enhancing old tree resilience during prescribed burns, offering practical guidance on techniques like duff raking and burning under specific conditions, ultimately striving to balance ecological restoration with the conservation of these keystone forest components.

This paper explores operational resilience in western U. S. frequent-fire forests, emphasizing how historical forest structures fostered health and adaptability. The authors argue that very low tree densities prior to widespread fire suppression minimized competition, which in turn supported vigorous tree growth and greater resistance to stressors like drought and bark beetles. By comparing historical data with contemporary forest conditions using the Stand Density Index, the authors found a significant increase in tree density and competition today. This sugests that current management practices, which are focused primarily on fuel reduction, may not adequately restore the ecological resilience historically maintained by frequent, low-intensity fires. The paper advocates for a fundamental rethinking of forest management to prioritize significantly lower tree densities and minimal competition to enhance long-term forest health.

This document summarizes the early findings of a multidisciplinary study in Washington's Capitol Forest, which evaluates six different silvicultural regimes ranging from traditional clearcutting to group selection and untreated controls on an operational scale. By managing young-growth Douglas-fir stands for multiple objectives, researchers aim to provide forest managers with quantitative data on the biological, financial, and social consequences of various timber harvest patterns. Key themes include the comparative costs and feasibility of implementing these systems, the physical impact on soil and regeneration, and the public's aesthetic response to different landscape conditions. This study seeks to identify management options that can sustain high timber yields while simultaneously enhancing wildlife habitat and visual appeal to meet modern societal expectations.

This report presents models to predict the likelihood of Douglas-fir mortality and bark beetle infestation following wildfires. The authors developed these tools using data from past fires in Montana and Wyoming, aiming to improve both pre-fire planning and post-fire management decisions. The report details the significant variables influencing tree survival and beetle attacks, such as crown scorch and cambium damage, and includes a supplementary field guide with visual aids and methods for field data collection, providing a practical resource for forest managers.

This document investigates the effectiveness of various thinning, pruning, and residue fuel management strategies designed to mitigate extreme wildfire hazards in the fire-prone forests of interior British Columbia. Using both simulated scenarios and analyses of actual operational treatments, the research modeled impacts on passive and active crown fire potential, as well as tree mortality. A key finding is that while removing small trees reduces the risk of passive crown fire, the concurrent removal of some larger trees is necessary to substantially reduce the threat of active crown fire. The study also confirmed that effective management of residue fuels is critical for treatment success, while pruning was found to have minimal impact on crown fire mitigation. This work provides valuable, region-specific data to help forest managers make informed wildfire management decisions regarding necessary treatment intensity.

This document synthesizes existing knowledge on reintroducing fire into long-unburned, fire-dependent forests of the United States, specifically focusing on how to minimize mortality of large, old trees. Historically, these ecosystems experienced frequent, low-intensity fires, which kept fuel loads low and fostered fire-tolerant species. However, over a century of fire suppression has led to unprecedented accumulations of deep duff and increased tree densities, making reintroducing fire a complex challenge that can paradoxically harm the very old trees practitioners aim to protect. The document delves into causes of tree injury and mortality from fire, such as basal cambium damage from smoldering duff and subsequent bark beetle attacks, and explores various management options including prescribed burning with the aim of restoring historical forest conditions and preserving venerable trees.

This document provides guidance on using fuel treatments and prescribed burning to protect whitebark pine forests, emphasizing methods to mitigate WBP mortality during fire. It outlines specific thresholds for crown and bark char damage that threaten tree survival and suggests that mechanical treatments may be necessary to reduce fuels prior to burning, particularly in areas with abundant competing conifers. The document categorizes forest stands as Good, Marginal, or Avoid Candidate Areas for prescribed burning based on the presence of cone-bearing WBP trees and vigorous regeneration, advocating for mechanical fuel reduction in high-value areas and generally advising against burning stands with high levels of cone-bearing trees or limited competition. Finally, the paper recommends coordinating fire planning with silviculturists and entomologists to account for factors like mountain pine beetle pressure and ensure a heterogeneous forest structure that minimizes the risk of large, high-severity wildfires.

This document provides a comprehensive guide for managing logging slash produced by thinning operations in ponderosa pine forests, with the critical goal of minimizing colonization and subsequent infestation of residual trees by bark beetles. Thinning creates substantial amounts of woody debris which serves as an ideal habitat for beetles, and as such, managers must employ various techniques to mitigate risk. The document explores factors influencing beetle attacks, such as timing of slash creation, stand density, and log size, while detailing practical management strategies including direct removal, solarization, and the complicated trade-offs of using techniques like chipping and green chaining. The purpose of this document is to equip land managers with diverse, site-specific treatment options to balance forest health objectives with the urgent need to reduce bark beetle risks.

This document outlines a framework for restoring ponderosa pine and dry mixed-conifer forests on Colorado's Front Range, addressing the increased size and severity of recent wildfires. It emphasizes understanding the historical ecological dynamics of these forests, particularly changes in density and fire regimes, to inform modern management. The document details principles and guidelines for restoration and emphasizes the importance of spatial and temporal scale, enhancing desired and rare structural elements like openings and tree groups, and working with natural environmental gradients and disturbance patterns. This document provides a process for planning, implementing, and monitoring restoration projects, highlighting the crucial role of adaptive management and interdisciplinary collaboration to ensure forest resilience and sustained delivery of ecosystem services.

This webinar presents results from a simulation study of north-central New Mexico that investigated the relative effectiveness of a variety of fuel treatment strategies and the tradeoffs of implementing fuels programs with competing management goals.

This paper addresses the severe decline of High Elevation Five-Needle White Pine forests in western North America, primarily due to mountain pine beetle outbreaks, white pine blister rust, and altered fire regimes exacerbated by changing climates. The authors advocate for multi-scaled management interventions to promote resilience to disturbances and genetic resistance to white pine blister rust. The paper details the critical need for long-term programs like inventory, mapping, and research, alongside active restoration treatments such as mechanical cuttings and prescribed fires, and proactive tree-level measures like planting rust-resistant seedlings and protecting high-value trees, all while integrating climate change considerations throughout the planning and implementation process.

This study focuses on aspen, a vital broadleaf tree, examining its distribution and health in north-central BC and the various threats it faces, including climate change, forest management practices, and ungulate grazing. It explores the ecological implications of potential aspen declines, specifically considering the relationship between aspen and beaver-created shallow water wetlands, offering recommendations for future research and management.

This report compiles over 80 years of fire research to explain how human interventions have altered natural fire regimes, particularly in dry Western U. S. forests. The document emphasizes that accumulated fuels and dense forest structures, a departure from historical conditions, lead to more intense and severe wildfires, posing risks to both ecosystems and human communities. It details various fuel treatments, such as thinning and prescribed fire, as crucial strategies for restoring fire-resilient forests by reducing surface, ladder, and crown fuels. The report advocates for a landscape-level approach to fuel management, acknowledging that while models and observations inform these efforts, uncertainties remain in predicting exact fire behavior.

This paper presents the long-term ecological effects of forest fuel and restoration treatments from the ongoing national Fire and Fire Surrogate study, analyzing data collected over approximately 20 years across four diverse sites in the Western and Eastern United States. The central goal of the original FFS study was to evaluate how mechanical treatments and prescribed fire impact forest ecosystems by reducing fire hazard, promoting desirable fire-adapted species, and improving understory diversity. Key findings reveal that the most effective treatment varies significantly by region: mechanical treatments combined with fire yielded better long-term outcomes in Western pine-dominated forests, while prescribed burning alone proved more beneficial in Eastern hardwood-dominated forests. The authors conclude that to maintain these desirable conditions and achieve long-term resilience, treatments must be adapted to the specific ecosystem and followed up with repeated applications.

This paper synthesizes the disparate groundwater responses to wildfire, noting that post-fire effects range from significant increases to decreases in water fluxes like recharge and baseflow. The authors evaluate this variability across five primary categories: climate, vegetation, hydrogeology, fire characteristics, and the cryosphere, focusing on both short-term and intermediate recovery periods. A critical finding is that post-wildfire responses often align with hydroclimatic settings where water input and evaporative demand are out of sync, while the pre-wildfire groundwater regime significantly influences the expected outcome and recovery trajectory. This paper provides a collection of testable hypotheses and identifies key areas, particularly the influence of snow dynamics and cryospheric processes, for future monitoring and modeling efforts to improve the prediction of groundwater recovery after fires.

This paper investigates how wildfires influence the upward migration of tree species in California's subalpine forests, a phenomenon often linked to climate change. Researchers examined post-fire tree regeneration across various fire severities, focusing on the contrasting responses of shade-tolerant and shade-intolerant conifer species. While overall montane species regeneration decreased in burned areas, shade-intolerant Jeffrey pine showed increased success in severely burned plots, aligning with predictions of higher climatic suitability. Conversely, shade-tolerant red fir regeneration declined significantly with higher fire severity, suggesting that the specific regeneration niche of a species, its ideal post-fire conditions, is critical in determining whether fire facilitates or hinders its range expansion.

This paper investigates the effectiveness of different forest fuel treatments, such as thinning and prescribed burning, in reducing the severity of subsequent wildfires. Leveraging a unique 1200-hectare experiment that was later impacted by a significant wildfire, the authors compared various treatment approaches, including thin-only, burn-only, and a combination of both, against an untreated control. Their analysis of fire severity metrics, considering pre-fire fuel conditions and fire weather, provides strong evidence that proactive fuel management, especially combining thinning and burning, significantly mitigates wildfire intensity and damage to trees, even decades after the treatments were implemented and under a range of weather conditions. The study supports the continued use of these treatments as valuable tools for forest restoration and enhancing resilience to increasingly severe wildfires.