Logging-induced Edge and Configuration of Old-growth Forest Remnants in the Eastern North American Boreal Forests

Worldwide, old-growth forest loss and fragmentation resulting from logging are considered major threats to biodiversity. In many regions of the boreal zone, remaining patches of old-growth forests left following logging are restricted to small areas exposed to edge effects. Our objectives were to evaluate, from a literature review, the distance of edge influence (DEL) induced by sharp logging-induced edges on adjacent old-growth residual forests and to compare, in order to exemplify edge effect influence, two contrasting scenarios of residual stand configurations (linear vs. agglomerated). Synthesis from studies conducted in boreal forests of Canada and Fennoscandia indicates a DEI of similar to 50 meters for residual old-growth forests located along recently (<= 20 years) cutover areas. Based on the comparison of two contrasted scenarios, we demonstrate the strong relationship between residual forest configuration and area under edge influence. For a similar area of residual old-growth forest, linear strips scenario was > 2.5 times more affected by edge compared to agglomerated scenario. We thus recommend considering various types of dispersion strategies that result in large forest residual stands interconnected with remnants > 100 m wide in order to reduce edge influence on the remnant old-growth stands, to mimic forest fire patterns, and to conserve associated biodiversity. To our knowledge, this study is the first meta-analysis to review and assess the DEI in boreal forest of North America and Fennoscandia. In addition, it quantifies, using a spatially explicit model, the impacts of logging-induced edges on the amount of interior forest for two common strategies of residual forest configuration that are well established in eastern Canada.