Failure of natural regeneration after clearcut logging in Wood Buffalo National Park, Canada

Abstract

Logging of boreal riparian old-growth white spruce took place in Wood Buffalo National Park from 1951 to 1991. In this study we focus on one of the areas, Timber Berth 408, logged from 1966 to 1991. Regeneration surveys of white spruce were conducted in clearcuts and undisturbed vegetation during June 1994. The age of a clearcut is unrelated to either white spruce stocking or density over a 25 year period. Post-logging natural regeneration in clearcuts has failed: median stocking (% frequency in 10 m 2 plots) and density (stems ha −1) of seedlings are 18.2% and 300 ha −1, and of transgressives are 14.3% and 200 ha −1. Median stocking and density of spruce (including residual growth) in the cutover areas are 36.4% and 848 ha −1. In order to achieve the level of stocking found prior to logging, ≈93% of the logged area, or 9300 ha, would require planting. There is a clear relationship between spruce stocking rates and densities in clearcuts and the distance to the nearest white spruce seed tree. White spruce seed tree distance is important in determining the ability of a clearcut to regenerate naturally. Failure of post-logging natural regeneration in Wood Buffalo National Park is attributable primarily to two factors: (1) large size of the clearcuts, placing most of any area logged beyond the effective dispersal distance of white spruce seed; (2) destruction of advance growth and lack of residual growth. Clearcutting and site preparation are shown to degrade boreal riparian ecosystem structure and function. Recommendations are provided whose goals are to maintain biodiversity and healthy ecological structure and function in boreal riparian ecosystems.