A fall in the fortunes of the missions began in 1812, following an earthquake and the destruction of mission buildings. The decline reached its nadir during the period of 1826 to 1833 when, after the overthrow of Spanish rule, Mexican decrees ended control of the land by the missions. Most lands were distributed by grants to allies of the leaders in Mexico. Camp Pendleton is coincident with a part of the second largest land grant resulting from the division of San Luis Rey mission lands and which included much of the Santa Margarita watershed.
Records of the 1880s for the then State of California indicate that wildfires burned uncontrolled for weeks at a time. Lack of protection from fire caused serious damage to irrigation works and water supplies of San Diego and other growing coastal communities. The first State of California Forestry Commission, established in 1886 by Governor Stone, reflected the growing public concern for the land. A report by the commission demonstrated the need for watershed protection by stating that major fires and erosion were injuring the climate, agriculture, and future prospects of Southern California.
In 1893 President Benjamin Harrison set the cornerstone of the Cleveland National Forest by creating the 20,000ha Trabuco Canyon Forest Reserve in the Santa Ana Mountains. In 1897 President Grover Cleveland established the 280,000ha San Jacinto Reserve. In 1899 local petitions to the General Land Office were effective in more than doubling the size of the Trabuco Reserve. In 1908 President Theodore Roosevelt combined the Trabuco and San Jacinto Reserves into the 80,000ha Cleveland National Forest, named in honor of former President Grover Cleveland. Subsequent acquisition and the transfer of the remaining San Jacinto Unit to the San Bernardino National Forest established the Cleveland National Forest close to its present size of about 200,000ha.
From 1880 until World War II, the city of Los Angeles experienced a steady growth and industrial development. The construction of an artificial harbor at Long Beach and San Pedro some 40km from the center of Los Angeles secured for the city its role as a terminus of a transcontinental railway.
San Diego's growth during the same period was slow. The mild climate attracted large numbers of inmigrants, but it lacked the industry to support a growing population. In the 1920s an important Naval Base was located in San Diego and thus a basic economic factor was established which remains to this day. By the time World War II began, San Diego had also become the focus for a large aircraft industry.
The growth of agriculture as an industry, and an increasing population, were made possible only by the importation of water, a resource always near the verge of exhaustion in the region. The ambitious Owens Valley project, which brought water from the Sierra Nevada several hundred miles south to Los Angeles, enabled that area's population to grow. In the 1930s the Colorado River was tapped, and water was brought as far south as San Diego. These two massive water projects relieved southern California from dependence on limited and variable local ground and surface water supplies and encouraged the public's perception of limitless supply. Only recently has this perception changed.
The ever-increasing population of southern California since World War II has brought continuing suburban movement outward from the major cities, and as a consequence there has been a decrease and displacement of agricultural acreage. These pressures occurred most strongly along the coastal strip stretching from metropolitan Los Angeles to San Diego, relieved in part by the presence of Camp Pendleton.
Camp Pendleton was established in 1942 when the U.S. Government paid $4,000,000 for 49,867ha of what was formerly the Rancho Santa Margarita Las Flores. The large land area of the base still retains much of the landscape character of the early California days of missions and ranchos.
Camp Pendleton is ideally suited to meet the requirements of its training mission because of its location and terrain. However, the growing population of the surrounding communities and the growth of southern California in general may threaten Camp Pendleton's ability to conduct this training. The increasingly dense population surrounding the base has led to increased demands by the communities, and by government and private entities serving these communities, for the use of land currently a part of Camp Pendleton, such as the leased agricultural and recreational areas. It also places greater pressure for natural resource management on Camp Pendleton. At the same time there is an increasing interdependence between the base and the region in terms of off-base housing, economic relations, traffic, and the range of environmental issues that know no property or other jurisdictional boundaries.
Southern California, and particularly the area comprising the study region, has grown more rapidly since World War II than any region of like size in the United States. Increasing population brings increased land use and the prospect of the depletion of available land capable of development. The study area had an estimated combined population of 1.1 million in 1990. 'The Context Map,' figure 1, demonstrates that the study area and its communities are not isolated but rather are contiguous with the rest of the urbanized area within the Los Angeles-San Diego region.
For the purposes of describing the study region, the research team has adopted the convention of combining land use, vegetation, and terrain into a single map called 'Land Cover.' In this classification, urban land uses take precedence over vegetation for any given location. The classification of land cover is a generalization of the more than 200 groupings of vegetation and land use described by the local and regional plans in the study area. It is mapped in the following aggregate categories:
Water
Riparian Vegetation
Oak-woodland
Mixed Forest
Orchards
Sage, Chaparral
Grassland
"Altered Land," extensive agriculture
Rural Residential (1 house per 2ha)
Single Family Residential (1 house per 1/10ha)
Multi-family Residential (1 house per 1/20ha)
Military Maneuver
Military Impact
Commercial, Industrial
Transportation
Figure 10 shows the land cover for 1990+.