- Fairfield Osborn Preserve
The Fairfield Osborn Preserve is a 411 acre (1.6 km²)
nature reserve situated on the northwest flank ofSonoma Mountain inSonoma County, California . There are eight plant communities within the property, oak woodland being the dominant type. [Larry Serpa and Lynn Lozier, "Fairfield Osborn Preserve: Natural History and Ecology" (1981)] Other communities includechaparral ,Douglas fir woodland , nativeBunch grass ,freshwater marsh ,vernal pool ,pond and riparian woodland. Theflora is extremely diverse including many native trees,shrub s,wildflower s,grass es,lichen s andmoss es. A diversefauna inhabits this area includingblack-tailed deer ,coyote ,bobcat and an occasionalmountain lion ; moreover, there are abundantavifauna (including someneotropical migrants),amphibian s,reptile s andinsect s.Copeland Creek and its tributaries drain the Preserve as they wend their way down steepravine s toward eventual discharge to theLaguna de Santa Rosa . The property was originally a SpanishLand Grant holding, devolving to private ownership and eventually gifted toThe Nature Conservancy ; the preserve is now owned and managed bySonoma State University as a research and education site. An understated naturaltrail system weaves through the property to provide access to creekcanyon s,ridge s andmarsh y areas. The preserve is situated at elevations 1,350 to 2,300 feet (411 to 701 meters) above sea level and features a landscape riddled withbasalt exposures that betray the volcanicprehistory ofSonoma County . ["Santa Rosa Quadrangle", Fifteen minute series,USGS Quadrangle Map, U.S. Government Printing Office, Washington DC (1958)] The climate at the Preserve is mild, with most rainfall occurring in the winter months and with some influence of thePacific Ocean providing moderating temperatures and some marinefog on early summer mornings. ["Environmental Impact Report for the Petaluma General Plan", Earth Metrics Inc. for the city of Petaluma and California State Clearinghouse (1986).]oils
The steep slopes of Copeland Creek have a predominant occurrence of Goulding
clay loam soil s, with a typical soil depth of only 16 to 20 inches (41 to 51 centimeters). ["Soil Survey, Sonoma County, California",U.S. Department of Agriculture ,Soil Conservation Service , Government Printing Office, Washington DC, May 1972] These are generally areas of 15 to 45 percent slopes that support dense mixed oak woodland, with large percentages ofCalifornia laurel andBigleaf maple . On the higher drier slopes, there are terraces of Raynor clay, which are associated with seeps and higher moisture retention known to the Turtle Pond and Cattail Marsh areas of the Preserve. Both soil types are known to supportgrazing when woodlands are cleared. In the late 1800s, the site was used forsheep andcattle grazing and the woodlands were cut forfirewood , which was taken by wagonload down the mountain to Petaluma.Hydrology
Copeland Creek and its tributaries drain this property; moreover, all of these streams rise onSonoma Mountain and eventually discharge to theLaguna de Santa Rosa , which discharges to the Russian River. The Copeland Creek watershed is the southernmost drainage in the Russian River drainage basin. All creeks south of Copeland, beginning with Lichau Creek, are part of theSan Francisco Bay watershed. Precipitation within the Copeland Creek watershed is considered moderate within the state of California; in fact, the maximum intensity for an historic one hourrainfall is classified as below average (at about 1.90 inches (48 millimeters) per hour). ["Rainfall Depth-Duration-Frequency for California", State ofCalifornia , Department of Water Resources, February, 1981] Since many of these upper reaches of Copeland Creek involve steep slopes, often above 50 percent, the momentum of streamflow in winter months is high. Even though soils in the watershed are moderately erosive, the extensivebasalt ic armoring of Copeland Creek minimizessediment ation and produces an outcome ofstream waters lacking in significantturbidity .Ecology
Principal plant communities within the Preserve include the dominant
California oak woodland savanna , and also consist ofchaparral , marsh, nativeBunch grass ,douglas-fir woodland and riparian woodland. Within the oak woodland the main tree species areCoast live oak ,Oregon oak ,California black oak ,Canyon live oak andCalifornia bay laurel . The woodlandunderstory exhibitstoyon ,coffeeberry ,poison oak and, in the higher exposed areas withecotone s to chaparral, containing chieflycoyote brush . [ [http://www.sonoma.edu/org/preserve/species_lists/plants_at_fop.pdf Vascular Plants of the Fairfield Osborn Preserve] ] This community sometimes gradates to small grassland savannas between the oak groves, which are rich with grasses and annualwildflower s. Example plants in this community are the Yellow Hayfield Tarweed, "Hemizonia congesta spp. congesta" and the Hayfield Tarweed, "Hemizonia congesta spp. luzulifolia", which are seen blooming in the late autumn. [Linda H. Beidleman and Eugene N. Kozloff, "Plants of theSan Francisco Bay Region", University of California Press (1983)]The freshwater
marsh was formed by massive land movement along the Rodgers Creek Fault. The two ponds on the property are manmade, having been created in the early 1900s. These wetland communities are importanthabitat for many species including sora andVirginia rail s,western pond turtle s, and the federally-listedendangered Red-legged Frog . Moreover, natural seeps feed these locations and the outcome is climaxvegetation that has stabilized. Turtle Pond has a layer ofduckweed on the water surface that is consumed by a variety offauna . Riparian zones of Copeland Creek have a very high percentage population of California bay laurel, but also provide habitat for a rich variety ofamphibian s,newt s and other fauna. ThePacific Giant Salamander , one of the largest knownspecies ofsalamander is observed hunting forprey in Copeland Creek. Other amphibians seen in riparian habitats include thePacific treefrog , "Hyla regilla",Rough skinned newt , "Taricha granulosa", andCalifornia slender salamander , "Batrachoseps attenuatus". A number of plants are particular to the deeply shaded riparian zone includingsnowberry and the uncommon CaliforniaGinseng , "Aralia californica ".History
Archeological surface surveys indicate that the site was used as a seasonal hunting and gathering ground by Pomo,Miwok , andWappo people, who traveled extensively to forage and barter. The earliesthistorical records show the property was within a SpanishLand Grant in the 1860s. During the latter part of the nineteenth century, agricultural uses intensified, especially in the form of grazing, although the extent of ecological damage was not as severe as the lower grazed slopes of Sonoma Mountain. By the 1890s the land was a working sheep and cattle ranch held by the Duerson family. In the 1950s, the land was purchased by William Matson Roth for use as a summer family retreat. William and his wife Joan transferred the land toThe Nature Conservancy in 1972, with the resulting preserve being named for Joan's father,conservationist andauthor Henry Fairfield Osborn, Jr . In 1977, The Nature Conservancy leased the preserve toSonoma State University (SSU), which conducts environmental education field trips for as many as 4,000 school children a year. [Tobias Young, "SSU in line to own nature preserve," Santa Rosa "Press Democrat",September 8 ,1996 .]In 1997, ownership was transferred to SSU, which continues to use it for research and environmental education. [George Lauer, "Nature's haven," Santa Rosa "Press Democrat",
February 3 ,2000 , pp. D1, back.] In 2004, 190 adjacent acres (76 ha) were added to the preserve by gift of William and Joan Roth.cite web | last = | first = | authorlink = | coauthors = | year = Sep 2004 | url = http://www.sonoma.edu/pubs/release/2004/793262616.html | title = Roth Family Donates 190 Acres to Nearly Double of SSU Nature Preserve on Sonoma Mountain | format = | work = Press Release | publisher = Sonoma State University | accessdate = 2006-10-09] Both parcels are managed under conservation easements from The Nature Conservancy and the Sonoma County Agricultural Preservation and Open Space District. The director of the Fairfield Osborn Preserve is SSU biology professor Nathan Rank.Practical aspects
The Preserve is open for research and educational programs, and public visitation is permitted by guided tour only. While most docents are students from Sonoma State University, many derive from the community at large. [ [http://www.trailcenter.org/newsletter/2001/winter2001/winter2001-03.htm Trail Companion: Farifield Osborn Preserve] ] Tours are offered at 10 am on Saturdays during the Fall and Spring. In addition to the nature hike guided tours by trained naturalists, there are periodic special workshops taught by Sonoma State University faculty and other scientists, covering such special topics as
geology ,mycology andamphibian s.The Preserve lies between
Petaluma andSanta Rosa, California ; access may be achieved from Petaluma Hill Road, and thence to Roberts Road and Lichau Road. On route along Roberts Road, one can obtain glimpses of the channel restoration work on lower Copeland Creek conducted during the late 1990s; this work featured erosion control, native riparian planting and eliminating access bycattle . The paved access route also features a stretch ofgravity hill , an optical illusion which makes the motorist feel like a stretch of roadway appearing to be uphill, in fact, is a downhill extent.References
ee also
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Basalt
*California Coast RangesExternal links
* [http://www.sonoma.edu/org/preserve/default.html Fairfield Osborn Preserve official site]
* [http://www.nature.org/ The Nature Conservancy official site]
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