107 resources found

This paper addresses the critical need for improved understanding of the long-term effectiveness of fuel reduction treatments in dry, fire-prone forests of western North America. The authors highlight that current knowledge limitations lead to inefficient maintenance and inaccurate wildfire forecasting. They propose six key research opportunities designed to refine our grasp of how long treatments remain effective. These opportunities include evaluating longevity within specific management goals, referencing desired ecological conditions, accounting for natural forest variability, exploring internal treatment factors, increasing post-treatment sampling frequency, and incorporating spatial heterogeneity into analyses. The paper aims to foster climate-adaptive management that enhances dry forest resilience to wildfire through more efficient and informed treatment strategies.

This paper investigates the effectiveness of various fuel treatments in mitigating wildfire behavior in British Columbia's seasonally dry forests, a region increasingly vulnerable to extreme fires. Through field measurements and fire behavior modeling, the study assessed how different combinations of thinning, pruning, and residue fuel management impact the potential for crown fires and tree mortality. Key findings suggest that high-intensity thinning is more effective at reducing both passive and active crown fire potential and tree mortality compared to low-intensity thinning, while pruning after thinning offered little additional benefit. The study also highlights that chipping or pile burning residue fuel can reduce crown fire risk, but cautions that chipping may lead to delayed tree mortality not captured by current models, indicating a need for further research on its long-term effects.

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 explores how wildfires and beetle communities interact to influence Douglas-fir beetle outbreaks in British Columbia's forests. Traditionally, DFB populations are expected to surge after fires due to an abundance of weakened trees, but this study reveals a more complex dynamic. The presence of woodboring beetles, which also colonize fire-injured trees, can significantly constrain DFB population growth through interspecific competition. Specifically, when woodborers infest over 50% of trees in a stand, DFB reproduction falls below replacement levels, suggesting that these competitors can suppress potential DFB irruptions and ultimately influence forest resilience after disturbances.

This document details a research project in British Columbia testing various silvicultural systems beyond traditional clearcutting to manage forests for multiple values, not just timber. The study evaluated the costs, productivity, tree damage, and soil disturbance associated with different harvesting methods used in the first phase of the project. The findings highlight the trade-offs between different approaches, noting that methods like clearcutting were most cost-effective for harvesting, while alternative systems resulted in varying levels of tree damage and soil disturbance.

This document details a research project in the Cariboo Region of British Columbia focused on revising free-growing guidelines to better account for the interactions between young conifer plantations and broadleaf trees, particularly trembling aspen. The central theme is understanding the competitive relationships between aspen and various conifer species across different biogeoclimatic zones. Through long-term experimental studies and field verification, the researchers gathered data on tree growth, health, and density to propose scientifically supported adjustments to the regulations that determine when a reforested area is considered successfully established. The goal of this study was to create more ecologically informed and practically applicable guidelines that recognize the potential benefits of broadleaf presence while ensuring successful conifer regeneration for timber production.

This paper investigates how different forest management strategies impact the resilience of forests facing climate change, specifically a mountain pine beetle outbreak in British Columbia. The authors use a retrospective simulation approach from 1980 to 2060 to compare business as usual practices with two alternative strategies: one focused on increasing the diversity of replanted trees, and another that combined early harvesting of susceptible pine with diversified reforestation. The study assesses resilience by examining ecological factors like growing stock and tree species diversity, alongside socio-economic indicators such as timber flow stability and net revenue, concluding that proactive management enhancing diversity and reducing high-risk species leads to greater overall forest resilience in the face of climate-related disturbances.

This report details a second timber harvest entry conducted on a mule deer winter range in British Columbia, thirty years after the initial logging. The study examines the application of General Wildlife Measures for shallow and moderate snowpack zones, focusing on a clumpy single-tree selection silvicultural system designed to balance timber harvesting with maintaining and enhancing mule deer habitat. Key aspects explored include the planning and operational implementation of this approach, including the creation of small canopy gaps and thinning from below, along with the lessons learned regarding ecological impacts, adherence to regulations, and operational feasibility. The report serves to document this long-term research project's progression and inform future management practices on similar winter ranges.

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 investigates the interplay between future wildfire risk and the greenhouse gas mitigation potential of rehabilitating forests in British Columbia, Canada. Using modeling that simulates future fire scenarios and tracks carbon in forests and harvested wood products, the study assesses whether post-fire salvage logging and replanting can lead to a net reduction in GHG emissions compared to natural regeneration. The authors explore the conditions under which these rehabilitation efforts yield climate benefits and compare this potential mitigation against the substantial GHG emissions from the projected increase in wildfires, questioning if resources might be better directed towards preventing fires in the first place.

This document details the establishment and early findings of the Roberts Creek Study Forest. The RCSF was created to demonstrate and evaluate various alternatives to clearcutting in mature Douglas-fir dominated forests on the Sunshine Coast. By implementing different silvicultural systems, such as dispersed retention and extended rotation, the study aims to assess their impacts on aspects like harvesting, windthrow, and the regeneration of conifer species like Douglas-fir and western redcedar, while also considering ecological, social, and economic objectives in forest management. The report outlines the study area, methodologies used for different treatments, and presents initial results regarding post-harvest stand structure, soil disturbance, windthrow patterns, seedfall, and both natural and planted regeneration.

This study aims to quantify the loss of coarse woody debris habitat due to reservoir construction and identify affected terrestrial vertebrate species. The authors explore management strategies to restore or enhance CWD, defining CWD as woody material greater than 10 cm in diameter lying on the ground, including stumps. The paper provides a framework for understanding and mitigating the ecological consequences of hydroelectric development on forest ecosystems.

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 FRDA Report #196 is a synthesis of project results investigating the effects of fertilization and thinning on a Douglas-fir ecosystem at Shawnigan Lake, British Columbia. The research reports on a long-term, multidisciplinary study examining how these forest management techniques influence tree growth, physiology, and ecosystem processes. Key themes include the long-term impact on growth and yield, the mechanistic response of the trees to nitrogen, and the fate of nitrogen fertilizers within the soil and water systems. This document provides a comprehensive overview intended to inform better forest management practices by synthesizing decades of experimental data.

This technical report introduces a drought risk assessment tool designed to help forest managers in British Columbia navigate the challenges of a warming climate. By using a stand-level water-balance approach, the researchers calculated the ratio of water availability to evaporative demand to establish drought tolerance thresholds for ten common tree species. The study concludes that many species face significant threats of stress and mortality on drier sites, whereas moist, water-receiving areas may serve as critical climate refugia for conservation. This document provides a practical framework for applying this data to silvicultural decisions, such as selecting resilient species for reforestation and identifying areas at higher risk for wildfires or invasive species.

This technical report evaluates how varying levels of aspen retention influence the development of mixed-species forest stands in British Columbia, specifically focusing on the growth of lodgepole pine and the emergence of aspen suckers. By comparing different thinning intensities against an untreated control, the researchers sought to identify thresholds for competition that allow for optimal timber production while maintaining the ecological benefits of broadleaf trees. The findings indicate that while pine vigour improved when fewer than 1000 aspen stems per hectare were kept, significant differences in tree height and diameter were not yet apparent four years after treatment. Additionally, the study confirms that complete aspen removal triggers the highest density of new suckering, whereas leaving residual trees helps suppress this regrowth. This document serves as a guide for silviculturists to refine free-growing standards and develop cost-effective management strategies for complex sub-boreal ecosystems.

This technical report evaluates a 14-year study on how clump thinning of bigleaf maple affects the development of both the maples and intermixed planted conifers in British Columbia. Because bigleaf maples regenerate via vigorous stump sprouting, they often overtop and outcompete young conifers, leading researchers to test whether reducing maple density could improve conifer survival and growth. The results revealed that manual thinning was largely ineffective for timber management, as the maple's rapid canopy closure and aggressive re-sprouting meant that the treatment provided no significant long-term growth advantage to the underlying conifers. Instead, the study suggests that bigleaf maple thrives under a coppice-based management system, where sprout growth is dictated more by internal clump dynamics than by the overall density of the stand. The authors conclude that while thinning does not benefit conifers, these mixedwood sites remain highly productive and may be better suited for short-rotation hardwood fiber production.

This document examines a twenty-year study in British Columbia regarding the complex relationship between red alder and two conifer species, Douglas-fir and western redcedar. While alder is often removed by foresters because it competes for light and space, it also provides essential benefits by naturally fertilizing the soil with nitrogen. The findings suggest that maintaining a specific density of 100 to 200 alder trees per hectare can actually support conifer growth, particularly on nutrient-poor sites. The authors conclude that traditional forestry assessment methods may be inadequate, recommending a larger plot radius to more accurately measure how these different tree species interact and compete over time.

This document evaluates the long-term viability of planting native broadleaf trees as a reforestation strategy in British Columbia's Cariboo region. By tracking species like aspen, birch, and cottonwood alongside traditional conifers over a ten-year study period, the authors discovered that planted broadleaves suffered from poor survival rates due to wildlife browsing, frost, and competition from grass. While these deciduous trees naturally excel at enhancing soil nutrients and providing frost protection for understory seedlings, the study concluded that they are currently less reliable than conifers when manually planted. This document suggests that while broadleaves remain vital for forest biodiversity and health, their successful management in this region relies more on robust natural regeneration than on artificial cultivation.

This document outlines a thirty-year study examining how crop-tree thinning affects the growth of western larch in southeastern British Columbia. By evaluating different levels of growing space, the author demonstrates that increasing the radius of clearance around individual trees significantly boosts their diameter, basal area, and merchantable volume. While the expansion of tree width was directly proportional to the amount of space provided, the study found that vertical height remained largely unaffected by the various thinning intensities. The results suggest that thinning must be implemented at an early age to be most effective, as older stands show a diminished capacity to respond to increased light and reduced root competition.