Recovery Plan for the Northern Spotted Owl - DRAFT

Selection of Forest TypesAt the time this report was prepared, fall 1991, a final set of DCAs was notavailable for analysis. Therefore, we chose three forest "subregions" typical ofthe range of conditions found in northern spotted owl habitat from Washingtonthrough northwestern California. Each subregion has a unique forest speciescomposition, environment, and mix of disturbance agents. Effects of naturaldisturbance and successful protection scenarios are likely to vary by subregion.This scenario will vary also within subregion, as there is more withinsubregionvariation than can be adequately represented by the three "modal"scenarios presented in this report.The first type is the wet-cool type including the whole of the Sitka Spruce (Piceasitchensis) Zone and most of the Western Hemlock Zone (Franklin and Dyrness1973), ranging into the lower Pacific Silver Fir Zone, with less emphasis on thedrier plant associations, particularly toward the south within the WesternHemlock Zone. We call this the West Cascades subregion (Figure F. 1). Thesecond type is the Mixed-Evergreen/Mixed-Conifer Zone of southwestern Oregon/northwesternCalifornia, which we call the Klamath subregion. The thirdtype is the Grand Fir/Douglas-fir Zone of the eastern Cascades, which we callthe East Cascades subregion. While these are not wholly homogeneous subregions,they encompass the range of variability expected in northern spotted owlhabitat protection scenarios.Figure F. 1. Generalgeographical range of thethree subregions defined inthis report. Where subregionsrneet, there is anoverlap that is not representedin thisfgure.E West Cascades |j*.;;/ / S KlamathLf~~~~~~EsCasadeI " I'll ......................... IIIIIIIIIIIII- I - - .1111 I I 11 .1428