TIMBERLAND MANAGEMENT AND GEOLOGY IN THE TECTONICALLY ACTIVE AND DYNAMIC ENVIRONMENT OF NORTHWESTERN CALIFORNIA

The science of geomorphology has been brought to the forefront of the timber industry with respect to land management. Geomorphic interpretations often direct land management decisions. Since geomorphology is directing land management, we have investigated further the geologic processes that contribute to the development of landscape scale geomorphology. These processes include tectonics, fluvial geomorphology, underlying geologic lithology and structure.

Because of the multitude of processes that shape hillslopes, we have found that detailed geologic mapping, as focused as lithic facies, inherently increases the effectiveness of the geologist in the timber industry. In attempting to increase the effectiveness of the geologist, we have begun critical geologic mapping at the watershed level to better interpret geomorphology for land management activities. Primary mapping objectives include primary and secondary structure, facies descriptions, general engineering characteristics, and the differentiation of strath and alluvial terraces. We have observed and further developed geomorphic attributes such as weathering characteristics for different lithologies, identified unmapped faults and terrace deposits at predictable and consistent elevations.

Once structure is identified, relationships between geomorphology and structure can be used to direct land management practices. Information drawn from such detailed mapping allow for a more fine-tuned risk assessment regarding mass wasting, aids in the location of proposed roads, identify future quarry sites, and aid biologists on the physical requirements for habitat. Academically, the benefits include the addition of field based structural data often in areas where the data is absent and refinement of existing knowledge.