DEVELOPMENT PATTERNS IN YOUNG CONIFER-HARDWOOD FORESTS OF INTERIOR ALASKA

The age structure and growth patterns of 53 young conifer-hardwood sta nds on upland, south-facing sites of interior Alaska were analyzed to determine the length of time for stand establishment after disturbance , the composition of early-successional stands compared to existing st ands, and the potential for late-successional stands dominated by coni fers. Mixed stands of Picea glauca, Populus tremuloides and Betula pap yrifera represented five plant community types and developed as single cohorts after stand-replacement fires. In the Populus tremnloides/Arc tostaphylos uva-ursi and Populus tremuloides/Shepherdia dia canadensis community types, hardwoods established rapidly and Picea glauca estab lished slowly. In contrast, stands in the Betula papyrifera-Populus tr emuloides/Viburnum edule, Betula papyrifera-Populus tremuloides/Alnus crispa, and Picea glauca-Betula papyrifera/Hylocomium splendens commun ity types,generally developed as a result of rapid, concurrent establi shment of conifers and hardwoods. These single-cohort, mixed species d evelopment patterns are not consistent with continual establishment of conifers and are likely the result of unique life-history traits and frequent stand-replacement fires.