277 resources found

This study, conducted at the Montane Alternative Silvicultural Systems site, investigated the phenomenon of growth check in young amabilis fir trees, characterized by a sharp decline in annual height increment approximately ten years after planting. Researchers hypothesized that this severe growth limitation was linked to aggressive competition from ericaceous shrubs, such as Vaccinium species, resulting in limited nutrient availability, particularly nitrogen deficiency. By comparing different harvest treatments and the use of early herbicide treatment, the study concluded that vegetation control was the most significant factor in maintaining growth - trees without herbicide were often severely stunted and exhibited greater Vaccinium cover. The findings establish that high shrub competition coupled with low foliar nitrogen are reliable indicators for diagnosing and predicting this critical growth failure on coastal montane sites.

This document details a study on the effect of commercial thinning on within-stand microclimate and fine fuel moisture in a mature lodgepole pine forest in southeastern British Columbia. Researchers compared thinned and unthinned stands, observing that thinning led to decreased rainfall interception and increases in solar radiation, wind speed, and near-surface air temperature. While fine fuel moisture content was lower in the thinned stand immediately after rain, these differences became very small under moderate and high fire danger conditions, suggesting minimal practical impact on ignition probability or crowning potential at those times. The study also validated the effectiveness of the Fine Fuel Moisture Code component of the Canadian Fire Weather Index System for predicting fuel moisture in both stand types during critical fire danger periods.

This FRDA Research Memo #218 investigates the effectiveness of various mechanical site preparation methods, specifically disc trenching, patch scarification, and ripping, on the establishment of conifer seedlings across three different biogeoclimatic subzones in British Columbia's interior. The study sought to determine the optimal mechanical treatment and the most favorable microsite planting positions for seedling survival and growth, particularly focusing on mitigating frost damage. After five years, results consistently showed that disc trenching and ripperdrag treatments offered the best outcomes across the subzones, with the specific microsite preference varying based on site moisture and elevation to best protect against environmental stressors like frost and drowning.

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 document investigates the effects of forest restoration thinning on the plant life beneath the tree canopy in two dry forest types. The initial findings consistently showed that the abundance of understorey shrubs and herbs was positively linked to light intensity and inversely related to the density of trees, emphasizing the negative impact of conifer ingrowth. However, immediately following mechanical thinning, the study observed an unexpected short-term reduction in understorey species richness, diversity, and cover, particularly when compounded by drought conditions. These results suggest that while thinning aims to mitigate the long-term negative impacts of increased tree density, the immediate mechanical disturbance requires careful management, especially concerning factors like the timing of treatment and post-treatment grazing.

This study investigates the factors influencing natural regeneration in uniform shelterwood systems, specifically focusing on Douglas-fir in the Sub-Boreal Spruce Zone. The study details methods for assessing seedfall density, seed predation, seedbed distribution, and the germination and survival rates of seedlings under various harvesting treatments. The core purpose is to understand how these elements interact to determine successful conifer regeneration, particularly noting that rotting wood and mineral soil are superior seedbeds compared to forest floor and moss, and that while harvesting can increase mineral soil exposure, it is often insufficient to maximize regeneration without additional scarification. The findings suggest that while all tested shelterwood methods promote adequate regeneration and frost protection, lower residual basal areas combined with significant forest floor disturbance are most favorable for Douglas-fir seedling growth and survival.

This paper investigates innovative harvesting and silvicultural systems designed to sustainably manage western Canada's boreal mixedwood forests, specifically focusing on the protection of immature white spruce while simultaneously enhancing deciduous regeneration. The studies were conducted in central and northern Alberta with the aim to develop cost-effective and operational methods for balancing the needs of conifer and deciduous users to maintain biodiversity and ecosystem sustainability. Key findings include the demonstration that specific equipment and techniques can significantly reduce damage to spruce during harvest, with particular emphasis on feller-buncher operations, carefully planned machine corridors, and wind buffers to mitigate blowdown.

This document details the Strathcona Elk Winter Range Enhancement Project, a multi-year initiative in British Columbia focused on improving habitat for Roosevelt elk. The project's main goals were to increase forage production, create better cover, and ultimately support a healthier elk population through various habitat enhancement trials, including seeding, pruning, and clearing. The report summarizes the methodology, results, and recommendations from the 2004 efforts, highlighting observations on forage growth, browse availability, and elk usage patterns, alongside financial expenditures and the project's long-term objectives for elk conservation within the Strathcona Provincial Park and surrounding valleys.

This document summarizes the Strathcona Elk Winter Range Restoration Project in British Columbia, outlining habitat restoration efforts from 2002 to 2003. The project focused on increasing forage production and improving cover attributes for elk through activities like planting, pruning, and scarification at six sites. Beyond restoration, a significant component involved monitoring techniques to assess project success and document its impact on Roosevelt elk populations, alongside efforts to increase public awareness about elk habitat needs.

This report details a collaborative study evaluating different timber harvesting methods in dry Douglas-fir ecosystems. The primary goal was to compare the productivity of clearcutting with various variable retention treatments (seed-tree, regeneration cut, removal cut), utilizing both cable-yarding and ground-skidding systems. The study also aimed to identify operational factors affecting varibale retention efficiency and to validate procedures for these systems, noting that factors like piece size, slope, and yarding/skidding distance often overshadowed the cutting pattern's influence on productivity.

This document investigates how the initial planting density, or espacement, affects the growth of a 27-year-old Sitka spruce plantation in British Columbia. The study examines various stand characteristics, including tree height, diameter, volume, and crown development across different planting densities ranging from 478 to 2990 stems per hectare. The core purpose is to provide foresters with data on optimizing stocking levels for Sitka spruce to enhance timber production and manage stand characteristics more effectively, suggesting a recommended range of 800 to 1400 stems per hectare for saw timber objectives. The findings highlight a trade-off: wider espacements produce larger individual trees and branches, while closer espacements yield a greater total volume per hectare when considering all trees in the stand.

This docuemnt details a case study on harvesting options in a highly constrained forest stand within the Rocky Mountain Trench, focusing on an experimental forest management pilot project. The primary goal was to evaluate different harvesting methods such as conventional, single tree, and group selection on soil disturbance and armillaria root disease. The study describes the site's characteristics, experimental design, and the specific silvicultural prescriptions implemented to achieve objectives like maintaining water levels and reducing disease susceptibility. It further outlines the harvesting operations conducted and presents preliminary results regarding the impact of each method on stand health and soil integrity.

This document details a case study on varaible retention as a method to restore old-growth forest conditions in British Columbia's East Kootenay region. It explains how historical land management, including fire suppression, drastically altered forest structures, leading to a decline in biodiversity and an increase in fire risk. The study outlines a silvicultural prescription designed to mimic natural disturbances by strategically removing timber, aiming to re-establish the characteristics of pre-settlement old-growth stands, such as varied tree sizes and increased light penetration. The purpose of this study is to demonstrate a sustainable management approach that not only mitigates fire hazards but also enhances wildlife habitat and supports the long-term health of the forest ecosystem.

This document is a part of a long-running Levels-of-Growing-Stock (LOGS) Cooperative Study in Douglas-fir stands, specifically detailing findings from installations at Sayward Forest and Shawnigan Lake in British Columbia. The core objective of the LOGS study is to understand how different thinning intensities impact cumulative wood production, individual tree size, and growth ratios in young Douglas-fir stands. This progress report summarizes data from these two Canadian sites, showing that volume growth is strongly tied to the amount of growing stock retained, and that thinning significantly influences tree size distribution and live crown development, suggesting potential for future productivity gains. The study also offers comparisons between various thinning regimes and unthhinned control plots, revealing the long-term implications of silvicultural practices on forest stands.

This document investigates the long-term effects of thinning on a 53-year-old lodgepole pine stand. The core purpose is to understand how different thinning intensities impact tree growth, stand health, and resistance to pests over nearly five decades. A key finding suggests that heavy thinning may help "beetle-proof" stands against the destructive mountain pine beetle, contributing to greater net volume increments despite initial mortality from other factors like snow. While acknowledging some study limitations due to initial variability, the report provides valuable insights into sustainable forest management practices for older lodgepole pine.

This document presents results from a long-term experiment examining the impact of spacing and thinning on coastal Douglas-fir plantations. The study, conducted over 28 years near Lake Cowichan, British Columbia, aimed to understand how different tree densities and thinning strategies affect various growth parameters like diameter, height, basal area, and total and merchantable volume. While acknowledging limitations due to site variation and a lack of replication, the report provides initial insights into managing Douglas-fir stands, emphasizing that higher density generally leads to smaller individual tree growth but greater overall stand volume, whereas thinning, especially heavy or early thinning, can positively influence tree size and merchantable volume.

This FRDA Report #029 details a long-term forestry study on the growth and yield of 56-year-old Western Hemlock stands in British Columbia, specifically examining the effects of commercial thinning over a 32-year period. The study found that while thinning did not significantly increase the overall cumulative yield, it did result in a larger average diameter for the remaining trees and an up to 8% greater usable total volume yield at the final harvest compared to unthinned stands. The decision to commercially thin these stands depends on whether a forester prioritizes a moderate increase in total volume or an improvement in the size and quality of the final harvested material.

This FRDA Report #021 details a 35-year study on the effects of commercial thinning on 50-year-old Douglas-fir stands on Vancouver Island. The study compared thinned and unthinned plots to analyze growth and yield metrics such as total volume, diameter, and mortality. While thinning led to a 12% increase in potentially usable total volume yield over the study period and produced larger diameter trees overall, it also resulted in an 18% reduction in total volume at final harvest compared to unthinned stands. The study suggests that commercial thinning provides earlier wood availability and larger trees, but does not significantly alter total gross annual growth or crop-tree size, offering valuable data for forest management models and strategies.

This paper presents the 8-year results of a silvicultural systems trial at Lucille Mountain in British Columbia's Engelmann Spruce-Subalpine Fir zone. The study investigates the effects of different logging methods like clearcutting, patch cutting, and various partial cuts on climate, regeneration, tree growth, wind damage, arboreal lichens, and litter decomposition. The research highlights the complex environmental responses to forest harvesting in this high-elevation ecosystem and provides initial insights for better managing these sensitive forests, including considerations for reforestation practices and the challenges of adaptive management.

This document presents a study investigating how different methods of controlling aspen growth impact the future yield of white spruce and lodgepole pine. The research utilizes the Mixedwood Growth Model for British Columbia to simulate various scenarios, including different initial aspen densities and brushing treatments. By comparing the resulting timber volumes and mean annual increment at a rotation age of 75 years across different subzone site series, the study aims to identify the most effective brushing approaches for maximizing the productivity of the coniferous species in mixedwood stands.