Introduction
Spatially explicit information on the species composition and structure
of forest vegetation at broad spatial scales is needed for ecological research,
bioregional assessment, and policy analysis. Satellite remote sensing has
been successfully used to map broad forest classes, but more detailed information
often is desired.
We undertook a study in the Oregon coastal province with these objectives:
- quantify spectral, environmental, and disturbance factors associated with regional gradients of tree species composition and structure;
- develop GIS-based tools that integrate field plot, remotely sensed, and mapped environmental data to map current vegetation;
- produce vegetation maps (model predictions).
We sought a method that would predict the co-occurrence of assemblages of species and structures, capture the full range of variability, and realistically portray spatial heterogeneity. We also desired a method that was consistent with a conceptual model of vegetation varying continuously along environmental gradients.