Chapter 32
Ecological Subregions of the United States



California Coastal Steppe, Mixed Forest, and Redwood Forest

One Section has been delineated in this Province:

This Section is located along coastal California. The area of this Section is about 4,600 mi2 (11,900 km2).

Section 263A--Northern California Coast

Geomorphology. This area has parallel ranges, and folded, faulted, and metamorhosed strata; there are rounded crests of subequal height. This Section is in the Coast Ranges geomorphic province. Elevation ranges from sea level to 3,000 ft (0 to 912 m).

Lithology and Stratigraphy. This area has late Mesozoic eugeosynclinal rocks of the Franciscan Formation, and shelf and slope sedimentary rocks.

Soil Taxa. Types include Alfisols, Inceptisols, Mollisols, Spodosols (Pygmy Forest), and Ultisols, in combination with isomesic and mesic soil temperature regimes, and udic, ustic, and xeric (moist end of range) soil moisture regimes. Fog contributes to soil moisture.

Potential Natural Vegetation. K\"uchler mapped vegetation as redwood forest, mixed evergreen forest, coastal prairie-scrub, coastal cypress and pine forest, and mixed hardwood forest. Predominant potential natural communities include Redwood, Douglas-Fir, Tanoak, Coast Live Oak, Coastal Sage (Franciscan) and North Coastal Shrub series.

Fauna. Mammals include Roosevelt elk, black-tailed deer, black bear, mountain lion, coyote, bobcat, raccoon, marten, fisher, and river otter. Birds include eagles, hawks, owls, peregrine falcon, osprey, and a variety of shore birds and waterfowl along the coastal part of the section. Species of concern include marbled murrelet and northern spotted owl. Streams and rivers are used by anadromous fish.

Climate. Precipitation ranges from 40 to 100 in (1,020 to 2,540 mm). Temperature averages 50 to 55 oF (10 to 13 oC). Summer daytime temperatures often modified by fog and sea breezes. The growing season lasts 250 to 310 days.

Surface Water Characteristics. Many slow or relatively slow streams and rivers in alluvial and weak bedrock channels flow directly to the Pacific Ocean. Most terminate in tide-affected brackish estuaries.

Disturbance Regimes. Historic occurrence of fire is changing from frequent, low to high intensity surface fires to infrequent, moderate to high intensity stand-replacing fires. This is a seismically active area with strong shaking and ground rupture.

Land Use. Composition and successional sequence of some communities (primarily grassland communities) has changed because of plant and animal species introduced between the early 1800's and early 1900's. These changes related to grazing and forestry. The north part of the Section contains expanding urban areas.

Cultural Ecology. Humans have been utilizing the area for some 8,000 to 10,000 years, and have been an integral part of north coast ecology for some 2,000 to 3,000 years. Early inhabitants thrived on the diversity of habitats from ocean and estuary to forest, and intensively gathered numerous resources. The variety of northwest California ethnographic cultures is the most complex in the United States, reflecting diverse prehistoric and historic uses, practices, and human adaptations. The fur trade was a unique part of northwest coast's early history; later, lumbering and agriculture were the main economic sectors. Contemporary attitudes and beliefs are dichotomized between emphasis on values: amenity for the newcomer and commodity for the long-time resident. However, all are overlain by a rural lifestyle, even in the trendy Marin headlands north of San Francisco. The economy is diverse, ranging from San Francisco Bay area financial and entertainment industries to rural agriculture, forestry, and fishing; tourism and recreation are important industries.

Compiled by Pacific Southwest Region.