Forest types of the North Cascades National Park Service Complex

Abstract

A forest cover type classification was developed for the North Cascades National Park Service Complex in north central Washington, U.S.A., based on 425 reconnaissance-level plots. Detrended correspondence analysis (DECORANA) was used to ordinate the data. Temperature and available moisture were identified as primary environmental gradients. Two-way indicator species analysis (TWINSPAN) was used to classify the data, resulting in eight forest cover types: ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), subalpine fir (Abies lasiocarpa), whitebark pine – subalpine larch (Pinus albicaulis – Larix lyallii), mountain hemlock (Tsuga mertensiana), Pacific silver fir (Abies amabilis), western hemlock (Tsuga heterophylla), and hardwood forest. The coniferous forest cover types, with the exception of ponderosa pine, were defined to have open and closed canopy components; each cover type includes a variety of plant associations. The cover types were integrated into a geographic information system used to create a cover type map that was 85% accurate. The forest cover types of the park complex are unique not so much for within-community diversity as for the close juxtaposition of cover types with interior and coastal climatic influences.