The foothills of the San Gabriel Valley are the foothills and hills in the San Gabriel Valley of eastern Los Angeles County, California. They include the foothills of the San Gabriel Mountains, and independent low mountain ranges of hills, in the east Greater Los Angeles region. The landforms are part of the Transverse Ranges System of Southern California and Baja California.
The ranges are roughly parallel the San Andreas fault to the north over the San Gabriel Mountains' ridgeline. They are generally along the Interstate 210 freeway, giving it the name "Foothill Freeway". The Interstate 210 and State Route 210 freeway covers 86 miles, between Sylmar in the west, through the foothills and San Gabriel and Pomona Valleys, to Redlands in the east.
The foothills provide greenbelts and contain Open Space Preserves and Regional parks. The undeveloped hill areas are part of California's chaparral and woodlands ecoregion – with montane chaparral and woodlands and Oak savannas habitats.
Their chaparral, grassland, and oak woodland plant communities evolved with wildfires, with some species of their native plants dependent on natural fires to regenerate and thrive. Chaparral is California’s most extensive native plant community. It is also one of the State’s most characteristic wilderness types, dominating foothills and mountain slopes. Properly defined, chaparral is a kind of shrub-dominated community of hard-leaved plants shaped by summer drought, mild, wet winters, and fires that naturally occur every 30 to 150 years plus – more frequent fires can lead to habitat loss and conversion to non-native grasslands. [1] Montane forests are generally pine and fir dominated communities that occur at higher elevations in southern California’s mountain areas from 3000 up to 8500 ft. At the lower parts of the range, dominant trees include big-cone Douglas fir and Coulter pine as well as canyon live oak and California bay. On higher slopes, lodgepole, limber, ponderosa, Jeffrey, and sugar pines occur along with white fir, incense cedar, western juniper, and black and canyon oaks. The low elevation species are sensitive to fire, and thus only found on rocky areas where the geology itself is fire-resistant. [1]
The fire danger in the foothills is very high. Almost all of the cities that the hills go through are cities for which CAL FIRE has made recommendations on Very High Fire Hazard Severity Zones. [2] There have been a number of wild fires in the foothills of the San Gabriel Valley, that is part of the area's natural environment. Global warming has occurred rapidly over the course of the past half-century. In California, less precipitation will occur as snow, meaning that less water is able to be stored in the snow-pack, and that dry summers could see even less water availability. Summertime peak temperatures will increase in many places. Fire "seasons" may become even longer. [2] The declaration of fire season in California is actually a change in preparedness levels for the California Department of Forestry and Fire Protection. When weather patterns in an area of the state become warm and dry, and vegetation (fuels) are at a low moisture content point, Emergency response dispatch levels are typically increased, facilities are staffed 24 hours a day and additional firefighters are hired. When cooling weather, rain and snow are sufficient to reduce the fire threat, CAL FIRE then reduces its preparedness levels by releasing additional firefighters, closing some of the stations, and repositioning aircraft. [3]
Chaparral is a shrubland plant community found primarily in California, in southern Oregon and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean climate and infrequent, high-intensity crown fires.
Pseudotsuga macrocarpa, commonly called the bigcone spruce or bigcone Douglas-fir, is an evergreen conifer native to the mountains of southern California. It is notable for having the largest cones in the genus Pseudotsuga, hence the name.
The Santa Monica Mountains is a coastal mountain range in Southern California, next to the Pacific Ocean. It is part of the Transverse Ranges. The Santa Monica Mountains National Recreation Area encompasses this mountain range. Because of its proximity to densely populated regions, it is one of the most visited natural areas in California.
The San Gabriel Mountains comprise a mountain range located in northern Los Angeles County and western San Bernardino County, California, United States. The mountain range is part of the Transverse Ranges and lies between the Los Angeles Basin and the Mojave Desert, with Interstate 5 to the west and Interstate 15 to the east. The range lies in, and is surrounded by, the Angeles and San Bernardino National Forests, with the San Andreas Fault as its northern border.
The Santa Susana Mountains are a transverse range of mountains in Southern California, north of the city of Los Angeles, in the United States. The range runs east-west, separating the San Fernando and Simi valleys on its south from the Santa Clara River Valley to the north and the Santa Clarita Valley to the northeast. The Oxnard Plain is to the west of the Santa Susana Mountains.
The Pomona Valley is located in the Greater Los Angeles Area between the San Gabriel Valley and San Bernardino Valley in Southern California. The valley is approximately 30 miles (48 km) east of downtown Los Angeles.
Chino Hills State Park is a state park of California, in the United States. It is located in the Chino Hills, foothills of the Santa Ana Mountains. It is a critical link in the Chino–Puente Hills wildlife corridor, and a major botanical habitat reserve for resident and migrating wildlife.
The Tehachapi Mountains are a mountain range in the Transverse Ranges system of California in the Western United States. The range extends for approximately 40 miles (64 km) in southern Kern County and northwestern Los Angeles County and form part of the boundary between the San Joaquin Valley and the Mojave Desert.
The Angeles National Forest (ANF) of the U.S. Forest Service is located in the San Gabriel Mountains and Sierra Pelona Mountains, primarily within Los Angeles County in southern California. The ANF manages a majority of the San Gabriel Mountains National Monument.
The Chino Hills are a mountain range on the border of Orange, Los Angeles, and San Bernardino counties, California, with a small portion in Riverside County. The Chino Hills State Park preserves open space and habitat in them.
Mount Tamalpais, known locally as Mount Tam, is a peak in Marin County, California, United States, often considered symbolic of Marin County. Much of Mount Tamalpais is protected within public lands such as Mount Tamalpais State Park, the Marin Municipal Water District watershed, and National Park Service land, such as Muir Woods.
The Simi Hills are a low rocky mountain range of the Transverse Ranges in eastern Ventura County and western Los Angeles County, of southern California, United States.
The Northern California coastal forests are a temperate coniferous forests ecoregion of coastal Northern California and southwestern Oregon.
The Verdugo Mountains, also known as the Verdugo Hills or simply The Verdugos, are a small, rugged mountain range of the Transverse Ranges system in Los Angeles County, California. Located just south of the western San Gabriel Mountains, the Verdugo Mountains region incorporates the cities of Burbank, Glendale, Pasadena, and La Cañada Flintridge; the unincorporated communities of Altadena and La Crescenta-Montrose; as well as the City of Los Angeles neighborhood of Sunland-Tujunga.
Foothill Boulevard is a major road in the city and county of Los Angeles, as well as an arterial road in the city and county of San Bernardino, stretching well over 60 miles (97 km) in length, with some notable breaks along the route. Like its name implies, Foothill Boulevard runs across the foothills of the San Gabriel and San Bernardino Mountains.
California oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico. Oak woodland is widespread at lower elevations in coastal California; in interior valleys of the Coast Ranges, Transverse Ranges and Peninsular Ranges; and in a ring around the California Central Valley grasslands. The dominant trees are oaks, interspersed with other broadleaf and coniferous trees, with an understory of grasses, herbs, geophytes, and California native plants.
The Klamath Mountains ecoregion of Oregon and California lies inland and north of the Coast Range ecoregion, extending from the Umpqua River in the north to the Sacramento Valley in the south. It encompasses the highly dissected ridges, foothills, and valleys of the Klamath and Siskiyou Mountains. It corresponds to the Level III ecoregion designated by the Environmental Protection Agency and to the Klamath-Siskiyou forests ecoregion designated by the World Wide Fund for Nature.
The California coastal sage and chaparral is a Mediterranean forests, woodlands, and scrub ecoregion located in southwestern California and northwestern Baja California (Mexico). It is part of the larger California chaparral and woodlands ecoregion.
The California montane chaparral and woodlands is an ecoregion defined by the World Wildlife Fund, spanning 7,900 square miles (20,000 km2) of mountains in the Transverse Ranges, Peninsular Ranges, and Coast Ranges of southern and central California. The ecoregion is part of the larger California chaparral and woodlands ecoregion, and belongs to the Mediterranean forests, woodlands, and scrub biome.
The California interior chaparral and woodlands ecoregion covers 24,900 square miles (64,000 km2) in an elliptical ring around the California Central Valley. It occurs on hills and mountains ranging from 300 feet (91 m) to 3,000 feet (910 m). It is part of the Mediterranean forests, woodlands, and scrub biome, with cool, wet winters and hot, dry summers. Temperatures within the coast can range from 53° to 65 °F and 32° to 60 °F within the mountains. Many plant and animal species in this ecoregion are adapted to periodic fire.