ABSTRACT
Boreal forestry is confronted with increasing demands to restore structurally simplied managed forest toward their natural state of complexity (Burton et al. 2010; Messier et al. 2013). Since the rapid expansion of industrial forestry across the circumboreal zone after World War II (WWII), forest management has predominantly been based on the even-aged forest management, where timber is periodically extracted by clear-cutting. This practice, together with short cutting rotations relative to the biological age of the main tree species or to the natural stand development, has created landscapes which are patchworks of relatively young structurally homogeneous stands. This contrasts with primeval boreal forests, which are characterized by more uneven-aged forest, old trees, abundant dead wood, and higher structural variability. These more variable conditions are common in unmanaged forests because high severity disturbances are infrequent and/or of limited scale, or because partial disturbances are prevalent in the forest. The strong contrast between managed and unmanaged forest is due to their divergent disturbance regimes (Cyr et al. 2009; Kuuluvainen 2009). The disturbance regime of the managed forest differs fundamentally
CONTENTS
12.1 Introduction ........................................................................................................................ 251 12.2 Intrinsic Dynamics of the Circumboreal Forest: More Diverse Than Expected ......254 12.3 Comparison of Unmanaged and Managed Boreal Forest Landscapes .....................256
