15 resources found

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 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 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 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 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.

This paper investigates the long-term effects of post-wildfire logging in dry coniferous forests east of the Cascade Range. It addresses a key debate by presenting findings that post-fire logging effectively reduces future surface woody fuel levels over several decades, thereby potentially mitigating the severity of subsequent wildfires. Furthermore, the research indicates that when best management practices are employed, post-fire logging has minimal lasting negative impacts on the recovery of understory vegetation. The purpose of this publication is to provide scientific information to land managers making decisions about post-fire forest management, particularly regarding fuel reduction and ecological impacts.

This paper investigates the impact of long-term fire suppression on the drought sensitivity of mixed-conifer forests in the Western United States. The study utilizes tree-ring analysis of stable carbon isotopes to demonstrate that the exclusion of frequent, low-severity wildfires has led to overcrowded forest stands. This increased density results in heightened competition for water and nutrients among trees, making them more susceptible to drought stress, insect outbreaks, and disease compared to historically open forests maintained by fire. The findings emphasize the importance of reintroducing fire and managing stand density for forest restoration and increasing resilience to future climate conditions.

This study addresses the ecology and management of interior Douglas-fir at the northern extent of its range in British Columbia, particularly within the Prince George Timber Supply Area. The study delves into concerns about a perceived decline in Douglas-fir abundance, exploring its ecological, cultural, and economic significance in this northern environment. It synthesizes existing knowledge on Douglas-fir, examining past and present management practices, its role in local ecosystems including wildlife habitat and soil health, and challenges related to its regeneration, often comparing it with other species like lodgepole pine and spruce. The document serves as a problem analysis and aims to inform the development of an interim management strategy and future research directions for sustaining Douglas-fir in these unique northern landscapes.

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 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 technical report presents a field guide based on the Malheur model, a tool developed to predict the probability of delayed mortality in fire-damaged ponderosa pine trees. The report details the application and validation of this model, which uses observable characteristics like bole and crown scorch to estimate mortality risk via a user-friendly graph. Findings from validation studies across different locations and fire types suggest the model offers a reliable way for land managers to assess post-fire tree survival for various management objectives, including evaluating burn success and planning post-fire activities.