Landtype Associations of the Northern Region
Landtype association mapping was compiled at a scale of 1:100,000 by Forest Soil Scientists using a Regionally consistent legend for dominant groups of landforms and geologic materials occurring in repeatable patterns on National Forest Lands.
Landtype Associations (LTA's) were derived from the 1:24,000 scale Landtype mapping (Order III National Cooperative Soil Survey) which is the SSURGO equivalent for National Forest land in Montana. Landtype surveys for Region One will be incorporated into the SSURGO/NASIS format over the coming years. Currently the LTA mapping is available for all National Forest lands in Montana.
This mapping is intended to support broad-scale watershed and landscape level assessments. It is designed to be used in conjunction with the Section and Subsection levels of the National Hierarchical Framework of Ecological Units as a tool for evaluating and comparing biophysical conditions across large landscapes. It should be used to stratify locations with similar geomorphic environments, as LTA's have characteristics that are directly linked to distinct stream and riparian types. This mapping is also useful for comparisions of erodability, sediment production and delivery.
The full PDF report – LANDTYPE ASSOCIATIONS OF THE NORTHERN REGION, 1997: A FIRST APPROXIMATION has been provided for further information.
The LTA CDROM contains a complete set of maps, data tables and narrative descriptions for each of the Landtype Associations.