Managing for landscape patterns in the sub-boreal forests of British Columbia

• Main Author: Andison, David W.
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/6238

Forest managers in North America are attempting to incorporate a growing number of ecological issues across many different temporal and spatial scales. In response, the traditional approach of managing for individual or groups of species and/or functions, is giving way to managing for a more natural time-space array of natural resources. Better known as "landscape management", the strategy relies heavily on understanding the historical, "natural" processes and patterns at the landscape level. The objective of this dissertation is to develop a better understanding of the natural landscape-level dynamics of a fire dominated landscape in northern British Columbia. The age-class distribution was used to show that stand replacing fires had a fire cycle of 80-100 years. Although stands much older than this average persist, there was strong evidence to suggest that very old stands become more susceptible to some form of disturbance. The most striking feature of the age-class distribution was its lack of stability. Although the vast majority of disturbances were very small, and simple in shape, most of the landscape was comprised of very large disturbances. Forest fires were significantly more active in areas with the driest soils. It was also suggested that fire activity may be higher on south and west-facing slopes. Information from the disturbance regime description was incorporated into a spatially explicit landscape model to create multiple landscape scenes of a "natural" disturbance regime. Disturbance size limits and age eligibility restrictions were then imposed in simulation. Generally as size and age restrictions increased, interior forest area decreased, edge density increased, age-class distribution favoured younger forests, spatial diversity increased, and temporal diversity decreased. The detailed results demonstrated the importance of using a variety of pattern metrics, in different forms, to grasp the full impacts of each type and degree of restriction. The two methods of investigating sub-boreal landscape dynamics used in this research demonstrated the dangers of using single landscape "snapshots" to represent "natural" conditions. It also raises important questions with respect to the wisdom of management practices which artificially stabilize both spatial and temporal attributes of landscapes.