SPATIAL AND COMPOSITIONAL PATTERN OF ALPINE TREELINE, GLACIER NATIONAL-PARK, MONTANA

This study sought to quantify the complex patterns of alpine treeline across an extensive area of Glacier National Park, Montana. Satellite image classification, digital terrain modeling, and geographic informa tion system (GIS) measurements of landscape structure provided importa nt tools for the analysis, The study area was topographically partitio ned into watersheds and hillslope units in which to measure treeline p atterns. Cluster analysis of selected spatial and compositional patter n metrics was used to infer major alpine treeline forms. Six significa nt treeline types were differentiated using patch richness, contagion, contrast, number of patches, fractal dimension, relative edge-density , and forest-tundra juxta position. Clusters were validated using spli t-sample replication and discriminant analysis. Patterns were found to differ among types of terrain, affirming hypothesized sensitivities t o topoclimatic gradients, natural disturbances, and geologic substrate .