USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

San Joaquin Experimental Range

image-photo: building at experimental range

The San Joaquin Experimental Range (SJER) was established in 1934 and was California's first range research station. It was originally conceived as a cooperative interdisciplinary research center to identify cost-effect methods of commercial livestock production in the annual grass-oak pine woodlands, while maintaining the integrity of the ecosystem. More recently, research objectives have expanded and diversified to include research projects making contributions to our knowledge of the patterns and processes working in this ecosystem.

Education is a secondary objective at SJER, serving as an outdoor laboratory for numerous class visits and field trips each year. Classes from California State University at Fresno (Fresno State) and Fresno City College include field trips to SJER as part of their course content. Opportunities exist for independent studies and thesis/dissertation studies.


The climate is Mediterranean, with about 486 mm of rain falling from October or November to April or May. Winters are cool and wet, with frequent frosts and monthly mean temperatures between 4 and 10 °C. Elevation ranges from 210 to 520 m above sea level, with most of the area between 300 and 457 m. Exposures are generally southwesterly. The area drains into a small tributary of the San Joaquin River. Summers are hot and dry, with maximum daily temperatures commonly exceeding 38 °C and monthly mean temperatures ranging from 24 to 27 °C.


Bedrock is mainly granitic. Soils on slopes are shallow, residual, and granitic and generally of the Ahwahnee series. Soils in swales are deeper and are alluvial and generally of the Visalia series. Slope and swale soils have a relatively low water-holding capacity. Granitic outcrops are common on slopes.


San Joaquin contains open woodland dominated by oaks (blue and interior live oaks) and foothill pine with scattered shrubs and nearly continuous cover of herbaceous plants. Swales occur in low areas between rises. Dominant shrub species include ceanothus (both wedgeleaf ceanothus and chaparral whitehorn) and manzanita. Herbaceous plants are generally annuals including grasses (e.g., pine bluegrass soft chess, foxtail fescue), and various legumes. Perennials, primarily rushes, are found in the bottomlands. Native perennial bunchgrasses are uncommon and occur on north slopes.

Long-Term Data Bases

Data bases maintained at San Joaquin include long-term climate information, a list of all publications based on information acquired at the forest, spring bird counts begun in the mid-1980s, long-term acorn production censuses, and grazing intensity information.

Annotated checklist of vertebrate fauna of the San Joaquin Experimental Range: The foothill oak woodlands of California are extremely rich in animal species. This recently-updated checklist provides a list of fish, amphibian, reptile, mammal, and bird species observed at SJER since its establishment in 1934.

Research, Past and Present

More than 500 scientific publications have emerged from work at San Joaquin covering studies in or on energy flow, ecosystem modeling, nutrient flow, fire ecology, geology and soils, hydrology, weather & climate, grasses, woody plants, methods, vertebrates (especially quail and passerine birds), invertebrates, livestock breeding/growth, livestock disease/ nutrition, seeding, sulfur fertilization, and a variety of other topics.

Recent and current work includes: Geographical Ecology of Acorn Production by California Oaks; Monitoring Herbaceous Production and Utilization; Effect of Burning on Seasonal Forage Production and Species Composition; Overstory Canopy Effect on Forage Production and Quality on Hardwood Rangeland; Introduced Annual Clovers; Beef Sire Evaluation; Comparison of Reproductive Strategies of Open and Cavity Nesting Birds; Point Counting as a Method for Monitoring Trends in Bird Populations in Oak-Pine Woodlands; Interspecific Competition for Nest Sites Between European Starlings (Sturnus vulgaris) and Native Cavity-Nesting Bird Species; Effects of Africanized Honey Bees on Pollination by Solitary Bees and European Honey Bees; Ammonia Emissions from Natural Soils and Vegetation.

NEON (National Ecological Observatory Network): The SJER has been designated as the core site for the Pacific Southwest. NEON is a nationally significant research program that will gather long-term ecological data on the response of the biosphere to change. The science focus for the Pacific Southwest is on a climate gradient, extending from the core site in the oak woodland at the San Joaquin Experimental Range, up through an elevation gradient into mixed conifer and red fir forests. Initial plans include installation of five flux towers will collect data on climate, canopy microclimate, air pollution, air quality, carbon cycling, soil characteristics, and water quality. Work will include additional infrastructure to support the work.

Current educational activities include experience for students with beef cow/calf production and management; animal science laboratories in Animal Science, Livestock & Carcass Evaluation, Beef Production, Intro to Livestock & Dairy Evaluation, Intro to Animal Health, Advanced Beef Management, Artificial Insemination and Embryo Transfer, and Advanced Livestock and Dairy Evaluation; and SJER Field Day to disseminate information generated at SJER to users.

Major Research Accomplishments and Effects on Management

Significant contributions have been and are being made to development of sustainable grazing systems in California's oak woodland savannas. The nearly 20 year-long record of bird counts provides an extraordinary resource for exploring the year-to-year variation of birds in oak woodland savannas


California State University, Fresno Agricultural Foundation, California State University, Fresno, University of California, Davis, Berkeley, University Extension, & Cooperative Extension

Research Opportunities

SJER provides a unique opportunity to conduct research and offer educational opportunities within the annual grass-oak-pine woodlands in central California.

  • Livestock are continuously present at SJER and can be used in experiments to evaluate the relations between livestock, grazing effects, and plants and animals
  • Responses of organisms to prescribed fire in oak woodland savannas

We encourage researchers and educators to explore the opportunities afforded by SJER and to take advantage of them by proposing research problems or educational activities. The past, present, and future success of the SJER is directly related to the knowledge derived from it.

To request use of SJER for research or educational purposes or to request use of the conference room, please fill out the appropriate form on this web page and follow the submission instructions. Approval of projects is necessary to ensure that they do not conflict with existing operations, research projects, and educational activities. Research proposed for the RNA must be submitted to the PSW RNA Committee for evaluation.


SJER is located near the geographic center of California in the western foothills of the Sierra Nevada in Coarsegold, Madera County, California, about 20 miles (32 km) north of Fresno. SJER encompasses a total of 1806 ha (4462 acres) and ranges in elevation from 213 m (700 feet) to 518 m (1700 feet). San Joaquin lands were purchased in 1934 (1,387 ha), with additional purchases in 1936 (16 ha) and 1937 (372 ha). In 1938, another 64 ha were obtained under authority of the Weeks Forestry Act. Fresno State manages a livestock operation at SJER and opportunities exist for research using livestock as a research tool. Livestock are excluded from several locations throughout SJER that offer unique opportunities for research. A 29.4 ha (72.5 acre) parcel has been designated as a Research Natural Area (RNA) as an example of the blue oak/foothill pine vegetation type and has been ungrazed since 1934. Two smaller ungrazed areas (2.4 and 4 ha in size (6 and 10 acres, respectively)) and numerous other small exclosures (less than one acre in size) also exist.

Lat. 37°5´45" N, long. 119°43´45" W


imgage-photo: landscape at experimental rangeLimited office space, barracks, and storage space may be available for approved research. The use of these facilities requires advance reservation arrangements.


Research Application

Educational Activities Request Form

Contact information

The San Joaquin research and management responsibilities are shared among the Pacific Southwest Research Station, California State University's Agricultural Foundation, and the University of California Department of Natural Resources.

San Joaquin Experimental Range
Renee Denton
USDA Forest Service
2081 East Sierra Avenue
Fresno, CA 93710
Tel: (559) 323-3204
San Joaquin Experimental Range
California State University-Fresno
School of Agricultural Sciences and Technology
2385 East Barstow Avenue
Fresno, CA 93740-0085