Relations of small mammal populations to even-aged shelterwood systems: A comment

Von Trebra et al. (1998) concluded that shelterwood. harvesting of sub-bore al spruce forest did not negatively affect small mammal populations. Howeve r apparent problems with their experimental design leave us without a clear understanding of small mammal responses to forestry practices. I offer sta tistical and biological rationales as to why their experimental design was likely inappropriate to test the hypothesis that "a shelterwood silvicultur al system would reduce small mammal populations" (Von Trebra et al. 1998:63 1). My objections emphasize issues of ecological scale, which suggests smal l mammal population results reported in their paper may not have reflected the habitat condition of individual experimental blocks, much less treatmen t units. Finally, I discuss implications to forest management, notably the conservation of sensitive species, of inferring conclusions and offering ma nagement recommendations from dubious results.