Data collected from 96 sites during 1990-95 showed that timber harvest in boreal forests of Alaska can greatly enhance or severely reduce moose (Alces alces) habitat quality, depending on forest management objectives, timing and methods of harvest, and post-logging site preparation. Overstorey removal associated with timely exposure of mineral soil favours establishment of early successional hardwoods important as moose browse. A combination of clear-cutting and soil scarification on mesic sites mimics fire, windfall, and fluvial erosion, important natural forces that drive regeneration of the boreal forest. When cut during dormancy, aspen (Populus tremuloides) and balsam poplar (P. balsamifera) regenerate prolifically by root and stump sprouting. However, harvest of paper birch (Betula papyrifera) or white spruce (Picea glauca) with little or no disturbance to the organic mat covering the forest floor often results in establishment of a long-lived herbaceous disclimax dominated by bluejoint reedgrass (Calamagrostis canadensis). This disclimax may persist for 25 to 100 years or more, limiting re-establishment of important deciduous browse species utilized by moose. With proper timber harvest, soil scarification, and good seedling establishment, carrying capacity for moose based upon forage supply can increase 20-45 fold (4-9 moose/kmsuperscript 2) over mature forest. Increases of this magnitude are also observed following wild fire. Estimates of carrying capacity following poor harvest practices with no scarification seldom exceed 0.2 moose/kmsuperscript 2, similar to that of mature forest. Properly regenerated clearcuts yield high quantities of moose browse for approximately 20 years following logging. The importance of appropriate timber harvesting practices for moose in the boreal forest ecosystem in Alaska is discussed.