Introduction
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A statement on the need for an experimental area in the San Joaquin Valley
foothills was prepared in 1934. The initial purpose for the San Joaquin Experimental
Range was to learn how to better manage these lands. 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. Of these, 32 ha have been designated as a Research Natural Area.
The San Joaquin is managed cooperatively by the Pacific Southwest Research Station
and California State University's Agricultural Foundation, primarily for research
and education.
Climate
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.
Soils
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.
Vegetation
San Joaquin contains open woodland dominated by oaks (blue and interior live
oaks) and digger 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.
Research, Past and Present
Nearly 400 publications have emerged from work at San Joaquin covering studies
on energy flow, ecosystem modeling, nutrient flow, fire ecology, geology and
soils, hydrology, weather and climate, grasses, woody plants, monitoring techniques,
vertebrates (especially quail and passerine birds), invertebrates, livestock
breeding/growth, livestock disease/nutrition, seeding, and sulfur fertilization.
Recent research addresses the following topics: geographical ecology of acorn
production by California oaks; monitoring herbaceous production and utilization;
effect of burning and overstory canopy on seasonal forage production and species
composition; introduced annual clovers; beef sire evaluation; comparison of
reproductive strategies of open- and cavity-nesting birds; methods for monitoring
trends in bird populations in oak-pine woodlands; interspecific competition
for nest sites between european starlings and native cavity-nesting bird species;
foraging ecology of European starlings; effects of Africanized honey bees on
pollination by other bees; and ammonia emissions from natural soils and vegetation.
Current educational activities include a variety of experiences for students
with beef cow/calf production and management: in animal science, livestock and
carcass evaluation, beef production, livestock and dairy evaluation, animal
health, and artificial insemination and embryo transfer. Other educational activities
include archaeology field classes, field day and leadership conferences to help
to disseminate information generated at San Joaquin.
Major Research Accomplishments and Effects on Management
Significant contributions have been and are being made to the development of
sustainable grazing systems in California's oak woodland savannas. The nearly
20-yearlong record of bird counts is an extraordinary resource for exploring
the year-to-year variation of bird populations and diversity in oak woodland
savannas.
Collaborators
Collaborating scientists from Fresno Agricultural Foundation, California State
University-Fresno, University of California at Davis and at Berkeley, and Fresno
City College engage in cooperative research at San Joaquin as do university
extension, and cooperative extension groups from these same institutions.
Research Opportunities
Livestock are continuously present at San Joaquin and can be used in experiments
to evaluate the relations among livestock, grazing effects, and plants and other
animals. Ecosystem responses to prescribed fire in foothill oak woodlands can
also be studied.
Facilities
Facilities include limited conference facilities, office space, barracks, and
storage space available for approved research. San Joaquin Experimental Range
is located in O'Neals, California, about 32 km north of Fresno.
Lat. 37°5´45´´ N, long. 119°43´45´´
W
Contact information
San Joaquin Experimental Range
USDA Forest Service
Sierra Nevada Research Center
2081 East Sierra Avenue
Fresno, CA 93710
Tel: (510) 559-6300
Or
San Joaquin Experimental Range
California State University-Fresno
School of Agricultural Sciences and Technology
2385 East Barstow Avenue
Fresno, CA 93740
Tel: (559) 868-6233
http://www.fs.fed.us/psw/programs/snrc/collab_science/collab3sjer/
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