[1] The Preserve features woodland, forest and grassland communities that lie at the edge of coastal fog influence.

The Clear Lake area was regularly visited for its distinctive fisheries, as well as the unusual mineral resources available there (magnesite, steatite, and two sources of obsidian).

The United States assumed control of Alta California in 1848 and the first American settlers began to claim lands in the area.

Throughout his life, Galbreath valued protection of natural resources and the knowledge needed to make wise land management decisions.

The 3,670-acre (1,490 ha) Galbreath Wildlands Preserve lies in the upper Navarro Watershed in the Coast Range of northern California.

Located approximately 17 miles (27 km) inland from the Pacific Ocean in southern Mendocino County, this topographically diverse landscape ranges from 900 to 2,200 feet (270 to 670 meters) in elevation and includes coniferous forests (Douglas-fir and redwood), mixed hardwood-conifer forests (Douglas-fir, tanoak, madrone), oak woodlands (mostly black and Oregon white oaks), and annual grasslands and riparian woodland.

Rancheria Creek flows northward through the preserve, along with numerous seasonal tributaries, and drains into the Navarro River.

The Navarro River watershed contains the highly erodible Franciscan mélange (a jumbled matrix of rock types created as the Pacific tectonic plate subducts beneath the North American plate) and alluvial fill, as well as the Coastal Belt of the Franciscan Assemblage, which is more stable and resistant to erosion.

Preserve vegetation types in order of abundance[4] are: Grasslands, woodlands, forests and aquatic habitats support a diversity of plants and animals.

Within the Rancheria Creek sub-basin, major land uses include sheep and cattle ranching, timber harvest, and open space and rural residential homes, with only a few locations in field and row crops.

Like much of the rest of the North Coast of California, timber harvest began in the mid-nineteenth century and has continued to the present.

Present day land use in the Navarro watershed is 70% forestry, 25% ranching, and 5% row crops, orchards and vineyards, with a small percent rural residential development.

Relatively steep, low order headwater streams have been affected by timber harvest, roads, and grazing management.

Agricultural practices, grading, and other land disturbances also contribute to high levels of sedimentation in the Navarro River watershed.

Sediment production rates decreased during the 1980s and '90s from historic highs during the 1950s through '70s due to changes in harvest practices and improved construction and maintenance of active logging roads.

Another key management challenge is controlling feral pigs (Sus scrofa) and invasive plants, such as scotch broom (Cytisus scoparius) and yellow-star thistle (Centaurea solstitialis).

Rainfall and floods are seasonal, falling primarily between October and May, and are typical of the wet Mediterranean-type climate of north coastal California.

The Navarro River watershed receives about 40 inches of rainfall with about 60% falling during winter months from mid-December through the end of March.