Hans Jenny Pygmy Forest Reserve

The Hans Jenny Pygmy Forest Reserve lies on the oldest and highest of five wave-cut terraces that rise from the chilly waters of the Mendocino County coast. In this complex “ecological staircase,” each terrace is approximately 100,000 years older than the one below it and supports a distinct association of soils, microbes, plants, and animals. The uppermost terrace of the reserve affords an opportunity to study two pristine climax communities, Bishop pine forest and pygmy forest, on podzolized (nutrient-poor, highly acidic) soils. Underlying this relatively inhospitable soil is a clay hardpan. As a result, much of the vegetation is stunted, and there are dwarf trees; some mature trees are barely waist-high with trunks a few centimeters in diameter.

The reserve also harbors an understory of unusual evergreen shrubs, with many endemic species, such as Mendocino cypress and Bolander’s pine. This site, which is protected by The Nature Conservancy (TNC), is named in memory of renowned UC Berkeley Professor Emeritus Hans Jenny, a world authority on soil science, who spent over half a century studying the inhospitable soils that support this rare, fragile forest.

Selected Research

• Landscape evolution: The pygmy forest “ecological staircase.”
• Soil studies: Soil development, nutrient cycling, and vegetation-soil relations.

Contact Information
Integrative Biology
4006 Valley Life Sciences Building
University of California
Berkeley, CA 94720-3110

Location
Mendocino County, 3.2 km (2 mi.) southeast of Mendocino; 241 km (150 mi) north of San Francisco; 3.5-hour drive from Berkeley campus.

Facilities
Limited trail system; walk-in soil pit; no on-site structures or campgrounds.

Reserve bibliography
The reserve bibliography includes citations of journal articles, books, theses, art, and other works published about or based on activities conducted at the reserve.

Databases
Plant List
Results from soil surveys.

Personnel
Faculty director on campus.

Size
28 hectares (70 acres)

Elevation
180 m (591 ft.)

Average Precipitation
98 cm (39 in.) per year 

Average Temperatures
September maximum: 15 ºC (59 ºF)
January min: 8 ºC (47 ºF)
Annual mean: 12 ºC (53 ºF)