| Summary: | Engelmann Spruce-Subalpine Fir (ESSF) forests of interior British Columbia have increasingly
become the target of forest harvesting in the past 40 years. Over the past decade, increasing
public concern over maintaining biodiversity and ecological health within forests has brought
about two primary pieces of legislation—The Forest Practices Code of 1995 and The Forest and
Range Practices Act of 2002—that shape the current paradigm directing forest management.
This paradigm maintains that biological diversity can be preserved by designing forest harvesting
practices that result in regenerated forests that closely mimic naturally disturbed forests. It has
been suggested that fire is the primary form of natural disturbance in ESSF forests. To date, there
has been little knowledge gained about the natural disturbance patterns in ESSF forests, leaving
forest managers with little guidance as to how to emulate these patterns. In this study, I sought to
quantify both landscape-level and stand-level differences between naturally disturbed and
harvested forests in the North Thompson variant of the wet, cold subzone of the ESSF
(ESSFwc2) using the Geographical Information System Arcview and field measurement
techniques. A decrease in the amount of old-growth forest as well as a decrease in the mean
disturbance interval from naturally disturbed to harvested forests was found. Both patch size and
patch size variability decreased with harvesting in older age classes and increased with
harvesting in young age classes. A decrease in the amount of coarse woody debris and snags
from naturally disturbed to harvested stands, as well as a significant difference in tree species
composition between naturally disturbed and harvested stands was found. If emulation
silviculture is the goal of forest management, this study concludes that the current harvesting
method of clearcutting is failing to do so and, therefore, alternative harvesting methods and/or
non-timber outputs should be considered.
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