The LandtypeAssociations feature class contains polygon corporate data which depicts Landtype Associations covering USFS Region 6 national forests. The information in this layer was compiled to delineate the landscapes of the Pacific Northwest (Oregon and Washington) that are managed by the USFS into relatively homogenous units. These units capture climate, vegetation, morphometry (slope, aspect, relief, and surface roughness), geology, and time in order to delineate unique landscapes. This delineation is intended to help resource managers and resource users identify the physical and biological characteristics that have created the features of those landscapes over time and to identify the ecological processes that drive or are the result from the combination of factors that have created the specific landtype associations.