Managing Structural and Compositional Diversity with Silviculture

Abstract

Ecology, economy, and demography interact to affect forest management objectives. In the temperate rainforests of northwestern North America (Franklin and Halpern 1988), the outcome of this interaction for most of the 20^th century was a management emphasis on wood production (Curtis et al. 1998, Haynes et al. 2003). Because of production efficiencies, even-aged, clearcut systems favoring harvest and regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) dominated regional silvicultural practices for decades (Tesch 1995, Curtis et al. 1998) (see Appendix 1 for all common and Latin names). By century end, however, economic and social conditions had changed (Haynes et al. 2003), and so had knowledge about forest ecology (Perry 1994, Franklin et al. 2002). Not surprisingly, different management objectives emerged. Indeed, although forest management in the 21^st century still includes wood production, it is now just one of many objectives for regional forests (Kohm and Franklin 1997). Because management objectives and silvicultural practices are intertwined (Baker 1934, Daniel et al. 1979), this broadening of objectives is accompanied by a broadening of practices. Whereas earlier silvicultural practices simplified forest structure (arrangement and variety of elements) and composition (variety and amount of species present), the emphasis now is on managing diversity (O’Hara 2001).