ABSTRACT
Variations in conditions created by disturbances such as forest fire, insect outbreak, windthrow, and canopy gaps generate structural and compositional diversity (Attiwil 1994; Bergeron et al. 1999; Frelich 2002; MacLean 2007; Kneeshaw et al. 2011), two aspects critical for the maintenance of biodiversity. It has been proposed that forest management should maintain or recreate conditions found following natural disturbance regimes as most species are adapted to conditions created by the dominant natural disturbances. This principle is the foundation for forest ecosystem management based on emulating natural disturbances (Gauthier et al. 2009). In a changing world, reducing one of the anthropogenically induced stresses may be key to longterm viability of many species. Structuring forests at both stand and landscape scales has made forest fires and insect outbreaks the principal causes of disturbance studied and considered in designing forest management systems based on the emulation of natural disturbances (Hunter 1993; Bergeron et al. 1998, 2006; MacLean 2007). Crown fires initially produce large areas of relatively homogeneous forest conditions in terms of composition and age-class structure; however, when large fires are infrequent, forest composition and structure is controlled by single or group-tree mortality (Kneeshaw 2001). Stands in such forests are characterized by heterogeneous canopy conditions and a mosaic of small forest units in different stages of development (Watt 1947; Pickett and White 1985).
