SPATIAL GEOLOGIC MAP DATABASES FOR LAND MANAGEMENT IN THE PACIFIC NORTHWEST: AN OVERVIEW OF RECENT PRODUCTS

The USGS provides geoscience interpretations needed by the USFS for sound policy and land-stewardship practices. In the last decade, USGS projects in the Pacific Northwest have included participation in the Interior Columbia Basin Ecosystem Management Project (ICBEMP) and the Headwaters Province project. A primary objective of the Headwaters project was the development of a spatial database of information portrayed on geologic maps that could be used for analysis in geographic information systems.

The USGS has compiled a regionally-consistent and integrated spatial geologic database ("digital geologic map") for the Northern Rockies, bringing 43 individual 1:100,000- to 1:250,000-scale maps into a common database format. Our database has been designed to represent the original content of the published maps and to provide easily-used and consistent attribute content. In addition, we have added information based on our interpretations of published reports. In particular, we have added attribute information that 1) classifies igneous rocks by age, composition, and name, and 2) allows the creation of derivative maps based on lithology.

A lithology theme derived from a spatial geologic database was first prepared for the ICBEMP. This theme, combined with research of tree growth responses to fertilization and natural tree-mortality dynamics on different soil parent materials, has demonstrated a significant influence of lithology on forest development (J.A. Moore, University of Idaho, written comm. 1999). Preliminary versions of the current spatial geologic database have been used to show the importance of geology as one of the biophysical characteristics affecting western white pine development in northern Idaho (Jain and others, 2002) and forest growth modeling (Froese and Robinson, 2002).

Froese, R.E. and Robinson, A.P., 2002,: Incorporation soil parent material into prognosis: USDA Forest Service Proceedings RMRS-P-25, p. 135-140.

Jain, T.B, Graham, R.T., and Morgan, Penelope, 2002, Western white pine development in relation to biophysical characteristics across different spatial scales in the Coeur d'Alene River basin in northern Idaho, U.S.A.: Canadian Journal of Forest Research, v. 32, p. 1109-1125.