Wikipedia
Dubakella soil series is the name given to a reddish brown stony loam soil which has developed on ultramafic rock containing magnesium minerals such as serpentine or asbestos. This soil occurs from southwestern Oregon south to the Coast Ranges of California near Healdsburg, and it also is found in the Sierra Nevada mountains and foothills.
In common with other ultramafic soils, Dubakella has a poor balance of nutrients which does not allow the vegetation it supports to match the luxuriance seen on adjacent non-ultramafic sites. Jeffrey Pine is usually the most common tree, accompanied by Douglas-Fir, Incense-Cedar, and Sugar Pine -- all in open, somewhat stunted stands. In some areas, as at Grass Valley, the less stately Gray Pine is dominant. On the poorest sites vegetation may be held to a chaparral-like state.
In addition to being inferior for forestry and poor for agriculture, Dubalkella may present a health hazard due to presence of asbestos. Any Dubakella land which has been developed or is scheduled in that direction should be tested.