Forest Investment Account

Abstract of FIA Project Y051202

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Quantification of disturbance processes along a temperature and moisture gradient in sub-boreal forests

Author(s): Lewis, Kathy J.
Imprint: Prince George, B.C. : University of Northern British Columbia, 2005
Subject: Forest Investment Account (FIA), Trees, Diseases and Pests, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program


Small-scale disturbance and stand dynamics within mature, spruce-subalpine fir forests were compared and contrasted across three ecological variants within the central interior of British Columbia. The central interior is ideal for the study of small-scale disturbance because sub-boreal and subalpine ecosystems span the dry interior plateau and grade eastward into the progressively wetter, cooler, high-elevation ecosystems of the Rocky Mountain Foothills. This climatic gradient offers a unique opportunity to study how disturbance regimes vary across distinct ecosystems. Specific research goals were to: (1) develop and modify existing dendroecological techniques to date small-scale disturbance; (2) quantify present forest composition and structure as it relates to unique disturbance events; (3) determine the spatial and temporal occurrence of small-scale disturbance within and between three climatically distinct, mature spruce-subalpine fir forest ecosystems; and (4) identify the primary disturbance agents responsible for the present forest composition and structure. The results of this study provide further evidence indicating that small-scale disturbances are important ecological processes in sub-boreal and subalpine forest ecosystems. However, within these ecosystems there is considerable overlap between disturbance types of varying spatial and temporal scales. For example, intermediate-scale disturbance events have played a large mediating role over distinct successional changes in stand structure; more so than that of small-scale disturbance events. Consideration of disturbance events at multiple scales, however, shows that small-scale disturbance does exhibit continuous stand level maintenance and renewal; furthermore, that shifts in species dominance tend to be abrupt and due to intermediate-scale disturbances such as those caused by spruce beetle and western balsam bark beetle.

For further information, please contact Kathy Lewis, University of Northern British Columbia (

Updated September 08, 2005 

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