7 resources found

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 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 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.