Annadel State Park
Map SatelliteAnnadel State Park, which lies at the northern end of Sonoma Mountain, contains a variety of plant communities. One of the more important is the northern oak woodland, which can be divided into two types. The first, an Oregon oak, Quercus garryana, woodland, consisting of almost pure stands of the oak with a grassland understory which includes Vulpia microstachys var. pauciflora, Festuca californica and Festuca idahoensis, is well developed on the northeast and east slopes. It is one of the best examples of this association in the State. The second type includes both the coast live and valley oak, Quercus agrifolia and Quercus lobata, as well as some black and blue oaks, Quercus kelloggii and Quercus douglasii, and California buckeye, Aesculus californica. Poison oak, Toxicodendron diversilobum, is the dominant understory shrub.
There is a total of eight species of oak in the park, the other three, scrub, interior live, and leather, Quercus berberidifolia, Quercus wislizenii and Quercus durata, are found in the chaparral. Other prominent chaparral species include Arctostaphylos manzanita, Arctostaphylos glandulosa, Ceanothus foliosus and, in a few localities, knobcone pine, Pinus attenuata.
On the steep slopes and in some of the canyons there are redwood forests, Sequoia sempervirens, or mixed evergreen forests with redwood, Douglas fir, Pseudotsuga menziesii, California bay, Umbellularia californica, and some ponderosa pine, Pinus ponderosa. Along the streams is a riparian association with Oregon ash, Fraxinus latifolia, and Western azalea, Rhododendron occidentale.
There are grasslands, several with concentrations of native grasses such as Danthonia californica and Nassella pulchra, among others. They support abundant displays of spring wildflowers. Small vernal pools occur in the meadows.
Ledsen Marsh (Bennett Mountain Lake) is a small lake with a fluctuating level, fringed with cattail, Typha sp, and bulrush, Scirpus sp. It is an important animal habitat.
Five rare plants are found in the park, Ceanothus divergens, Ceanothus sonomensis, Fritillaria liliacea, Lilium rubescens and Navarretia leucocephala ssp. plieantha.
The presence of the marsh and a small man-made lake provide water in an otherwise relatively arid region for a variety of animal species. Some 29 mammals, including feral pigs, Sus scrofa, have been observed in the park, as have 25 species of reptiles and amphibians as well as over 140 species of birds. Noteworthy among the birds are the resident bittern, Botaurus lentiginosus, and the pileated woodpecker, Dryocopus pileatus.
Sonoma volcanics, exposed or underlying, cover virtually all of the park, save for a thin band of Plio-Pleistocene nonmarine sedimentary rocks along the northeastern edge. Two parallel faults traverse the park.
Integrity: Some 80 kilometers (50 miles) of dirt roads, now trails, lace the park. Until the late 1960's the area was grazed. It had been the scene of basalt quarrying and timber-cutting in the late 19th and early 20th centuries.
Use: Educational, research, observational, light recreation.
Ref: Wright, K. E. 1975. Annadel State Park Resource Inventory. Unpub. Calif. Dept. of Parks and Recreation, Sonoma, Calif.
Tunison, J. T. 1973. A Synecological Study of the Oak Woodlands of Bennett Mountain, Sonoma County, Calif. Unpub. M.A. Thesis, Sonoma State College.
August 1976
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman
