Introduction
The Blacks Mountain Experimental Forest, located in Lassen County, California,
was formally designated in 1934 as the Pacific Southwest Station's principal
site for management studies of the interior ponderosa pine type. Blacks Mountain
occupies 3,715 ha on the Eagle Lake District of the Lassen National Forest.
About half of the forest lies in a gently rolling basin at an elevation of 1,700
m. The remainder extends up the moderate slopes of Blacks Mountain to the north
and to the east, reaching an elevation of 2,100 m at the summit of Patterson
Mountain. Slopes rarely exceed 30 percent. Aspects are primarily west and south
facing.
Climate
The climate is characterized by warm dry summers and cold wet winters. Annual
precipitation, mostly snow, averages about 460 mm in the basin. About 90 percent
of the precipitation falls from October through May. Air temperatures during
the year usually range from -9 to 29°C.
Soils
Most of the soils are between 1 and 3 m deep over basalt. Typic Argixerolls
with mesic soil temperature regimes predominate at lower elevations. Andic Argixerolls
with frigid soil temperature regimes predominate at higher elevations.
Vegetation
Interior ponderosa pine (SAF 237) occupies 3,715 ha and is the only forest
cover type on the forest. Species composition varies within the type. White
fir and incense-cedar, absent in stands within the lower portion of the basin,
become increasingly abundant at higher elevations. The remaining 437 ha are
poorly drained flats occupied by sagebrush and grass.
Long-Term Data Bases
Blacks Mountain has been subdivided into 100 compartments of about 40 ha each.
An intensive road system, the first in the West designed specifically for truck
hauling, was laid out so that every compartment was bordered by a road. Compartments
and roads have been continuously maintained. In 1933 and 1934, the Blacks Mountain
was completely inventoried on a 1-ha grid. Timber type maps and inventories
were prepared by compartments and updated following harvests. Computerized stem
maps for a 20-year period and inventories for a 50-year period are available
on 8-ha parcels (48). An ecological unit inventory was completed in 1994.
Research, Past and Present
Studies going back as far as 1910 resulted in new theories of management, silviculture,
and insect control for interior ponderosa pine. The initial objective of Blacks
Mountain was to develop these theories into a system of management and to test,
demonstrate, and improve this system through continuous operation of a timber
tract on a commercial scale. Early timber harvests were primarily for insect
control. An insect risk-rating system developed at Blacks Mountain was tested.
The mosaic of small even-aged groups of trees (then the prevailing stand structure)
was proposed as the subject of management rather than individual trees. This
concept of "unit area control" was tested operationally during the 1950s.
An ambitious study of stand growth and development after several intensities
of timber harvesting was begun in 1938. Each year for 10 years, four to six
8-ha plots were installed to test cutting prescriptions ranging from a commercial
clearcut, to various intensities of partial cutting or no harvest. This methods-of-cutting
study (MOC) was abandoned in the mid-1960s when research became focused on even-age
management, but was resurrected in 1990 when interest returned to uneven-age
management. In 1992, the MOC compartments became the basis for a new long-term
interdisciplinary study of how forest structural complexity affects the health
and vigor of interior ponderosa pine ecosystems, the ecosystem's resilience
to natural and human-caused disturbances, and how such ecosystems can be managed
for sustained resource values. In 1995, Blacks Mountain was selected as part
of the North American Long-Term Soil Productivity (LTSP) Network for 1 of 12
LTSP experiments in California.
In October 2002, the Cone Fire consumed 647 ha at Blacks Mountain. Subsequently,
a study of fire salvage impact and wildfire behavior in managed stands was initiated.
Burned areas are receiving varying levels of salvage to test response of fuel
conditions and soil compaction.
Learn more about on-going research at BMEF
Major Research Accomplishments and Effects on Management
An insect risk-rating system was developed at Blacks Mountain to identify large,
old ponderosa pines at risk of being killed by the western pine beetle. When
early logging operations demonstrated that as little as 35 m3/ha
could be logged economically and that cutting using the insect risk-rating system
reduced the annual rate of tree killing, such sanitation/salvage operations
were employed over a wide area. A system for classifying ponderosa pine trees
as to vigor, developed at Blacks Mountain in 1936, continues to be used widely.
The concept of "unit area control" was tested operationally during the 1950s.
A 50-year record of stand development has demonstrated and quantified the increase
in stand density, the influx of white fir, and the increased mortality of large,
old ponderosa pines found in interior ponderosa pine forests throughout the
West in the absence of periodic wildfire.
Collaborators
Scientists and foresters from Humboldt State University, Oregon State University,
Wildlife Conservation Society, and Lassen National Forest have collaborated
on studies at Blacks Mountain.
Research Opportunities
Blacks Mountain contains typical stands of interior ponderosa pine with a variety
of stand structures from young plantations though natural stands of poles to
partially cut and uncut late seral stands. Collaborators are sought to explore
the responses of vegetation, wildlife, insects and other ecosystem components
to stand structure, grazing, and prescribed fire.
Facilities
Housing and office space is available at the Lassen National Forest's Bogard
Work Center, 19 km southeast of the forest. Gasoline and general merchandise
can be obtained in the town of Susanville, 64 km southeast of Blacks Mountain.
Lat. 40°40´ N, long. 121°10´ W
Contact Information 1
Blacks Mountain Experimental Forest
USDA Forest Service
Pacific Southwest Research Station
3644 Avtech Parkway
Redding, CA 96002
Tel: (530) 226-2530
http://www.fs.fed.us/psw/programs/ecology_of_western_forests/experimental_forests/blacks_mountain/
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