%0 Research article
%T Effects of clearcut edges on trees in the sub-boreal spruce zone of Northwest-Central British Columbia
%A Burton, Philip J.
%D 2002
%J Silva Fennica
%V 36
%N 1
%R doi:10.14214/sf.566
%U https://silvafennica.fi/article/566
%X Clearcut-forest boundaries were evaluated for their effects on mature  and regenerating trees in the northern interior of British Columbia,  Canada. Two hundred and eighteen rectangular plots measuring 200 m2 each  were arrayed in transects across 12 cutblock edges created 9 to 21  years earlier, with the wall of standing timber facing either north or  south. The density of canopy trees on the inner edge was found to be  reduced by 19% (on north-facing edges) to 46% (on south-facing edges)  from average densities found in forest interiors. This reduction was  primarily due to windthrow after logging, which was elevated by 27%  (over interior background levels) at north-facing edges, and by 216% at  south-facing edges. Of the trees situated within 10 m of south-facing  cutblock edges, 11% of the Pinus contorta, 18% of the Abies lasiocarpa,  and 42% of the Picea engelmannii x glauca trees have apparently  collapsed, primarily those having height-to-dbh ratios greater than  71:1. As a result, irradiance in the forest understory was elevated  (over interior levels) at south-facing edges to distances of  approximately 65 to 70 m into the forest. Increased irradiance from  adjacent cutblocks enhanced the understory growth of Picea for  approximately 60 m into the inner edge of forests, 75 m for Abies.  Mature Pinus trees on south-facing edges showed an unexplained 48%  decrease in radial growth compared to average growth rates in forest  interiors, an effect that was detectable up to 45 m into the forest.  Elevated densities of conifer seedlings were evident for up to  approximately 70 m into clearcuts from north-facing forest edges.  Seedling growth in clearcuts was largely unaffected by shade from stand  edges. Though the extent of edge effects varies considerably with the  statistical techniques used to detect them, it appears that opening  effects on trees can extend between 40 and 120 m into this forest type,  while canopy effects reach shorter distances into clearcuts.