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.

North Mountain Experimental Area


The North Mountain Experimental Area (NMEA) was established on January 8, 1964, when land previously administered by the Bureau of Land Management, U.S. Department of the Interior, was withdrawn from all appropriation under the Public Land laws including mining/mineral leasing laws by Public Land Order 3221. This withdrawal occurred by authority of the President, and pursuant to Executive Order 10355 of May 26, 1952.

The NMEA contains a total of 4348 hectares. Nearly the entire area is covered with chaparral that is representative of southern California, low elevation, interior nontimbered wildlands. No unique or special features are found within the NMEA. The Bureau of Land Management land examiner described the area as "badlands," created apparently by uplifting along the Hot Springs Fault line. Three major drainages dissect the NMEA: Potrero, Poppet, and Indian Creeks. All three are ephemeral. Since 1983, nearly all of the vegetation on the Experimental Area has burned. A major fire in 1932 burned over 80 percent of the area, and again in 1967 the Bailiff Fire burned about 60 percent of the NMEA. Use of the Area is subject to valid existing rights and is limited to activities directly related to research in problems of prevention and control of forest and range fires.

Early studies at the North Mountain Experimental Area centered on fuel breaks and fuel properties. Plant control research was conducted in two main categories: (1) the eradication of either selective brush plants or all vegetation, and (2) the reduction of plant growth with growth-inhibiting substances. The research centered around the use of herbicides which were believed to give the most effective and economical control of brush regrowth in established fuelbreaks. Another study concerned shrub seed production, dispersal, and deposition on chaparral vegetation to develop better techniques for reducing the volume of hazardous brush fuels.

Other studies involved development of a low volume shrub that would slow down or repel fires and the use of sheep to reduce fuel volume on fuelbreaks. Studies to determine fuel properties affecting fire behavior of chamise (Adenostoma fasciculatwn) and other species were included. North Mountain was also the site. of wind pattern investigations to compare collected wind data with predictions From theoretical models of valley convections.


The climate of the NMEA is typically Mediterranean. Due to its inland location, summers can be quite hot and dry, and winters cool and wet. Mean maximum temperatures over 30° C and relative humidity values below 35 percent are typical for California inland stations.

Mean temperatures for Hemet (8 km southwest) are as follows:

January July
Minimum 3°C 15° C
Maximum 16°C 32° C

The annual precipitation is only about 250 millimeters. Rain falls primarily between October and April. January is typically the wettest month, with some 50 millimeters of precipitation.


Soils throughout most of the Experimental Area are derived from granitic rocks. They vary considerably in depth, are low in organic matter, are moderately coarse to very coarse, and neutral to slightly acid with the pH ranging from 6.5 to 5.8. They are low in fertility and have relatively low water holding capacity. Some soils on rolling-to-steep uplands are moderately coarse Lithosols developed from mica schists. The surface texture of these soils is predominately sandy loam, but grades into clay loam a few inches below the surface. These soils are also low in fertility, and are moderately permeable with medium to rapid runoff. Structural development is lacking throughout the profile.


The plant community is primarily of the Shrub Formation (Paysen and others 1980). The major subformations are the Chaparral Subformation (Chamise, Manzanita, Ceanothus, Mountain Mahogany, and Scrub Oak Series) and the Soft Chaparral Subformation (California Buckwheat Series). Several other series are present in minor and varying amounts.

Long-Term Data Bases

Aerial photographs arc available: 1:20,000 vertical aerial photographs (1961), and oblique aerial photographs (1964). A variety of maps are available: 7.5- and 15-minute topographic maps, 7.5-minute orthophotographic maps, and field-drawn vegetation maps at the series level. Wildfire history maps go back to about the 1930's.

Research, Past and Present1

Examples of Research

  • Fuel physical and chemical properties, and arrangement
  • Short- and long-term recovery from prescribed fives under varying conditions.
  • Factors that affect hydrologic processes, vegetation dynamics, air pollution, and nutrient cycling
  • Ecological and physiological studies of chaparral.

Research efforts focus on plant-soil-water relations in chaparral. Since 1983, nearly all vegetation at North Mountain has burned. In the October 2006 Esperanza fire, almost 65% of the experimental forest burned with pockets of unburned islands.

Major Research Accomplishments and Effects on Management

Significant contributions were provided from studies on fuelbreaks and fuel properties, as well as wind pattern investigations and plant control and eradication. Longterm data sets include field-drawn vegetative maps and wildfire history maps.


Future collaborators include the University of California, Riverside.

Research Opportunities

Research will focus on the short and longterm recovery from the Esperanza and will test pilot vegetative eradication techniques.


No office, laboratory, or living facilities are within the NMEA. The Forest Fire laboratory and the University of California in Riverside are within an hour's drive of the Area.

The Vita Grande Ranger Station (San Bernardino National Forest) is located approximately kilometers from the east entrance to the NMEA.


The NMEA is located in Riverside County, The nearest full facility community is Banning--located 5 kilometers north of the NMEA boundary. Beaumont and Hemet are also within 8 kilometers of the boundary. Elevation ranges from 460 meters to 1328 meters.

Road access to the NMEA is best from Banning/Idyllwild Highway, State Route 243. Due to the limited use of the area, road maintenance is infrequent and minimal, at this writing.

Contact Information

Project Leader
Prescribed Fire for California Chaparral and Associated Ecosystems
Forest Fire Laboratory
4955 Canyon Crest Drive
Riverside, California 92507

The overview presented here was originally published in:
Berg, Neil H., Tech coord. 1990. Experimental forests and ranges, Field research facilities of the Pacific southwest Research Station. Gen. Tech. Rep. PSW-119. Berkeley, CA: pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 67p.

A later publication similarly describes most Forest Service experimental areas in 2004:
Adams, Mary Beth; Loughry, Linda; Plaugher, Linda, comps. 2004. Experimental Forests and Ranges of the USDA Forest Service. Gen. Tech. Rep. NE-321. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northeastern Research Station. 178 p. GTR-NE-321 - 5.5 mb pdf

1This information has been updated since the original publication.