British Columbia forest practices are based on sustainable forest management. The goal is to integrate ecosystem processes with management practices. The dominant proposal to promote healthy ecosystems is to use forest practices that emulate the natural disturbance regimes. Yet there is a lack of knowledge regarding the natural disturbance processes and resultant stand structure in many of these forest ecosystems. The result is a situation where managers have few or inadequate tools to accomplish sustainable forest management. The proposed research adapts and applies recent methods in disturbance ecology to compare the frequency and impact of biotic versus abiotic disturbance agents along an ecological gradient sub-boreal, dry warm to wet cold ecosystems. We used 5 plots (0.25 ha each) in each of three variants (SBSdw3, SBSwk1, ESSFwk2) to examine the impact of small scale disturbance agents on stand dynamics. Plots were fully stem-mapped, and trees over 15cm dbh were recorded by species, diameter and condition. Increment cores were taken from all live and dead trees where possible. During the next, and final, field season, we will establish and measure understory sub-plots, and determine agents of mortality of dead canopy trees where possible. Tree ring analysis, and spatial data techniques are being used to quantify stand dynamic variables such as mortality and recruitment rates, gap size, canopy turn-over rates, transition probabilities, and rates and pattern of disturbance by specific forest health agents. These will be compared across the three different ecosystem variants, and will be used to quantify natural disturbance processes, develop indicators and ranges that can be used to design alternative silvicultural systems, and to monitor impact of forest health agents.
Kathy J. Lewis, R. Douglas Thompson.
Lewis, Kathy J., Thompson, R. Douglas. 2004. Quantification of disturbance processes along a temperature and moisture gradient in sub-boreal forests: technical report. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report