SPATIAL VARIATION IN TREE SEEDLING AND KRUMMHOLZ GROWTH IN THE FOREST-TUNDRA ECOTONE OF ROCKY-MOUNTAIN NATIONAL-PARK, COLORADO, USA

We measured tree seedling and krummholz leader growth in various envir onments within the alpine forest-tundra ecotone of Rocky Mountain Nati onal Park to assess the potential pattern of response to climate chang e. Tree seedling and krummholz growth vary by species and site, helpin g to create a spatially heterogeneous forest-tundra ecotone. Krummholz patches are growing more rapidly than seedlings and show especially r apid growth in wet meadow environments. Generally, patterns of seedlin g and krummholz leader growth reflect patterns of soil moisture and li ght availability, as well as edaphic factors such as soil texture and pH. Krummholz height growth does not appear to be balanced by shoot mo rtality, suggesting that under current conditions, krummholz patches m ay grow taller Should an increase in krummholz patch height be suffici ent to result in a change of growth form, the krummholz zone may chang e to patch forest in favorable locations.