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.

Field courses:
The site is visited by university courses in soil development, soil resources, and ecosystemology.

Contact Information
Todd Dawson
Integrative Biology
4006 Valley Life Sciences Building
University of California
Berkeley, CA 94720-3110
Phone: 510-642-6090

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.
Google Map

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

Plant List
Results from soil surveys.

On-site reserve director; reserve steward.

28 hectares (70 acres)

180 m (591 ft.)

Average Precipitation
98 cm (39 in.) per year

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

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