Ecologists and wildlife managers often rely on habitat classifications that are based on existing resource inventories and expert opinion. In the Tongass National Forest of southeastern Alaska, as in many managed ecosystems, forest types are defined primarily on the basis of structural characteristics, like tree stocking, size, and composition. While useful in management for timber production, this method of ide.gifying forest types produces a classification with limited relevance to wildlife management. Sitka Black-tailed Deer (Odocoileus hemionus sitkensis) are an important component of the ecology and economy of this region. We classified forests by applying cluster analysis to a suite of 12 environmental variables of ecological importance to deer, sampled on a 180-km² study area. The analysis ide.gified an ecological typology that consisted of 3 old- and 5 2nd-growth forest types and 1 non-forest cover type. We found that the structural classification currently in use confounded post-logging categories of differing value to deer and categorized old-growth forests in ways that may not relate clearly to deer ecology. Our method makes it possible to produce an ecological classification that incorporates information from an existing resource database, facilitating the integration of the 2 typologies. Such ecologically based habitat classifications are valuable tools for the conservation of animal species, especially those inhabiting intensively managed ecosystems.