In the fields of horticulture and botany, the term deciduous means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves in the autumn. The term deciduous means "the dropping of a part, no longer needed" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer, deciduous teeth in some mammals. Wood from deciduous trees is used in a variety of ways in several industries including lumber for furniture and flooring, bowling pins and baseball bats and furniture, cabinets and paneling. In botany and horticulture, deciduous plants, including trees and herbaceous perennials, are those that lose all of their leaves for part of the year; this process is called abscission. In some cases leaf loss coincides with winter -- namely in polar climates. In other parts of the world, including tropical and arid regions, plants lose their leaves during the dry season or other seasons, depending on variations in rainfall.
The converse of deciduous is evergreen, where foliage is shed on a different schedule from deciduous trees, therefore appearing to remain green year round. Plants that are intermediate may be called semi-deciduous. Other plants are semi-evergreen and lose their leaves before the next growing season, retaining some during winter or dry periods; some trees, including a few species of oak, have desiccated leaves that remain on the tree through winter. Many deciduous plants flower during the period when they are leafless, as this increases the effectiveness of pollination; the absence of leaves improves wind transmission of pollen for wind-pollinated plants and increases the visibility of the flowers to insects in insect-pollinated plants. This strategy is not without risks, as the flowers can be damaged by frost or, in dry season regions, result in water stress on the plant. There is much less branch and trunk breakage from glaze ice storms when leafless, plants can reduce water loss due to the reduction in availability of liquid water during cold winter days.
Leaf drop or abscission involves complex physiological changes within plants. The process of photosynthesis degrades the supply of chlorophylls in foliage; when autumn arrives and the days are shorter or when plants are drought-stressed, deciduous trees decrease chlorophyll pigment production, allowing other pigments present in the leaf to become apparent, resulting in non-green colored foliage. The brightest leaf colors are produced when days grow short and nights are cool, but remain above freezing; these other pigments include carotenoids that are yellow and orange. Anthocyanin pigments produce red and purple colors, though they are not always present in the leaves. Rather, they are produced in the foliage in late summer, when sugars are trapped in the leaves after the process of abscission begins. Parts of the world that have showy displays of bright autumn colors are limited to locations where days become short and nights are cool. In other parts of the world, the leaves of deciduous trees fall off without turning the bright colors produced from the accumulation of anthocyanin pigments.
The beginnings of leaf drop starts when an abscission layer is formed between the leaf petiole and the stem. This layer is formed in the spring during active new growth of the leaf; the cells are sensitive to a plant hormone called auxin, produced by the leaf and other parts of the plant. When auxin coming from the leaf is produced at a rate consistent with that from the body of the plant, the cells of the abscission layer remain connected; the elongation of these cells break the connection between the different cell layers, allowing the leaf to break away from the plant. It forms a layer that seals the break, so the plant does not lose sap. A number of deciduous plants remove nitrogen and carbon from the foliage before they are shed and store them in the form of proteins in the vacuoles of parenchyma cells in the roots and the inner bark. In the spring, these proteins are used as a nitrogen source during the growth of new leaves or flowers. Plants with deciduous foliage have advantages and disadvantages compared to plants with evergreen foliage.
Since deciduous plants lose their leaves to conserve water or to better survive winter weather conditions, they must regrow new foliage during the next suitable growing season. Evergreens suffer greater water loss during the winter and they can experience greater predation pressure when small. Losing leaves in winter may reduce damage from insects. Removing leaves reduces cavitation which can damage xylem vessels in plants; this allows deciduous plants to have xylem vessels with larger diameters and therefore a greater rate of transpiration during the summer growth period
Thousand Oaks, California
Thousand Oaks is the second-largest city in Ventura County, United States. It is in the northwestern part of Greater Los Angeles 40 miles from Downtown Los Angeles and is less than 15 miles from the Los Angeles neighborhood of Woodland Hills, it is named after the many oak trees present in the area, the city seal is adorned with an oak. The city forms the central populated core of the Conejo Valley. Thousand Oaks has since expanded to the west and east. Two-thirds of neighboring Westlake Village and most of Newbury Park were annexed by the city during the late 1960s and 1970s; the Los Angeles County–Ventura County line crosses at the city's eastern border with Westlake Village. The population was estimated to be 129,339 in 2015, rising from 126,683 at the 2010 census. Thousand Oaks is 55 square miles, for comparison, is 20 percent larger than San Francisco. Thousand Oaks was considered in 2002 as one of the safest cities in the U. S. based on consistent FBI reporting. It was ranked the fourth-safest among cities with a population greater than 100,000 in the United States by the FBI's 2013 Uniform Crime Reports.
The median home price is around $669,500, more than double the U. S. median home price. One of the earliest names used for the area was Conejo Mountain Valley, as used by the founder of Newbury Park, Egbert Starr Newbury, in the 1870s. During the 1920s, today's Thousand Oaks was home to 100 residents. In the 1920s came talks of coming up with a name for the specific area of Thousand Oaks. A local name contest was held, where 14-year-old Bobby Harrington's name suggestion won: Thousand Oaks; the valley was — and still is — characterized by its tens of thousands of oak trees. When the city was incorporated in 1964, Janss Corporation suggested the name Conejo City. A petition was signed by enough residents to put Thousand Oaks on the ballot. An overwhelming majority － 87% － of the city's 19,000 residents voted for the name Thousand Oaks during the September 29, 1964, election. Chumash people were the first to inhabit what is now called Thousand Oaks, settling there over 10,000 years ago, it was home to two major villages: Sap ` Satwiwa.
Sap'wi is now by the Chumash Interpretive Center, home to multiple 2,000 year-old pictographs. Satwiwa is the home of the Native American Indian Culture Center which sits at the foothills of Mount Boney in Newbury Park, a sacred mountain to the Chumash. A smaller village, Yitimasɨh, was located; the area surrounding Wildwood Regional Park has been inhabited by the Chumash for thousands of years. Some of the artifacts discovered in Wildwood include shell beads and arrowheads. Another small Chumash settlement, known as Šihaw, was located. A cave containing several swordfish and cupules pictographs is located here. Two other villages were located by today's Ventu Park Road in Newbury Park; these had a population of 100-200 in each village. Other villages included Kayɨwɨš by Conejo Grade; the Chumash had several summer encampments, including one located where Thousand Oaks Civic Arts Plaza stands, known as Ipuc. Another summer encampment was located at the current location of Los Robles Hospital; each village was ruled by a chief or several chieftains, who traveled between villages to discuss matters of common interest.
A council of elders directed organized events. Most villages had a cemetery, gaming field, a sweat house, a place for ceremonies. Locally discovered tribal artifacts are at display at Satwiwa Native American Indian Culture Center and the Chumash Indian Museum; the region's recorded history dates to 1542, when Spanish explorer Juan Rodriguez Cabrillo landed at Point Mugu and claimed the land for Spain. The Battle of Triunfo, which took place by Triunfo Creek, was waged over land between native Chumash and the Spanish newcomers. From 1804 to 1848, Thousand Oaks was part of Alta California, a Spanish polity in North America, it was Valley of Rabbits. The Spaniards and indigenous Chumash clashed numerous times in disputes over land. Conejo Valley was given the name El Rancho Conejo in 1803; this year, Jose Polanco and Ignacio Rodriguez were granted El Rancho Conejo by Governor José Joaquín de Arrillaga of Alta California. The land contained 48,671.56 acres. El Conejo was just one of two land grants in what became Ventura County, the other being Rancho Simi.
As a result of the Mexican War of Independence in 1822, Alta California became a Mexican territory. In 1822, Captain José de la Guerra y Noriega filed Conejo Valley as part of the Mexican land grant, it remained a part of Mexico until the short-lived California Republic was established in 1846. It became a part of the U. S. after California gained statehood in 1850. The valley was now known as Rancho El Conejo; the ranch period began when the de la Guerra family sold thousands of acres through the 1860s and early 1870s. Two men owned most of Conejo Valley in the 1870s: John Edwards, who came from Wales in 1849, Howard Mills, who came from Minnesota in 1870. While Edwards owned most of present-day Thousand Oaks and Newbury Park, Mills owned most of Westlake Village and Hidden Valley. Edwards' home was located on an acre of land where The Oaks Mall is located, while Mills built his home where Westlake Lake sits today; the third person to buy former Rancho El Conejo land was Egbert Starr Newbury. He bought 2,259 acres of land here in 1874, land which stretched from Old Town Thousand Oaks and into today's Newbury Park
In geography, a confluence occurs where two or more flowing bodies of water join together to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river. Confluences are studied in a variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion and scour pools; the water flows and their consequences are studied with mathematical models. Confluences are relevant to the distribution of living organisms as well; the United States Geological Survey gives an example: "chemical changes occur when a stream contaminated with acid mine drainage combines with a stream with near-neutral pH water. According to Lynch, "the color of each river is determined by many things: type and amount of vegetation in the watershed, geological properties, dissolved chemicals and biologic content – algae." Lynch notes that color differences can persist for miles downstream before they blend completely.
Hydrodynamic behaviour of flow in a confluence can be divided into six distinct features which are called confluence flow zones. These include Stagnation zone Flow deflection zone Flow separation zone / recirculation zone Maximum velocity zone Flow recovery zone Shear layers Since rivers serve as political boundaries, confluences sometimes demarcate three abutting political entities, such as nations, states, or provinces, forming a tripoint. Various examples are found in the list below. A number of major cities, such as Chongqing, St. Louis, Khartoum, arose at confluences. Within a city, a confluence forms a visually prominent point, so that confluences are sometimes chosen as the site of prominent public buildings or monuments, as in Koblenz and Winnipeg. Cities often build parks at confluences, sometimes as projects of municipal improvement, as at Portland and Pittsburgh. In other cases, a confluence is an industrial site, as in Mannheim. A confluence lies in the shared floodplain of the two rivers and nothing is built on it, for example at Manaus, described below.
One other way that confluences may be employed by humans is as a sacred place in a religion. Rogers suggests that for the ancient peoples of the Iron Age in northwest Europe, watery locations were sacred sources and confluences. Pre-Christian Slavic peoples chose confluences as the sites for fortified triangular temples, where they practiced human sacrifice and other sacred rites. In Hinduism, the confluence of two sacred rivers is a pilgrimage site for ritual bathing. In Pittsburgh, a number of adherents to Mayanism consider their city's confluence to be sacred. At Lokoja, the Benue River flows into the Niger. At Kazungula in Zambia, the Chobe River flows into the Zambezi; the confluence defines the tripoint of Zambia and Namibia. The land border between Botswana and Zimbabwe to the east reaches the Zambezi at this confluence, so there is a second tripoint only 150 meters downstream from the first. See Kazungula and Quadripoint, Gallery below for image; the Sudanese capital of Khartoum is located at the confluence of the White Nile and the Blue Nile, the beginning of the Nile.
82 km north of Basra in Iraq at the town of Al-Qurnah is the confluence of the rivers Tigris and Euphrates, forming the Shatt al-Arab. At Devprayag in India, the Ganges River originates at the confluence of the Bhagirathi and the Alaknanda. Near Allahabad, the Yamuna flows into the Ganges. In Hinduism, this is a pilgrimage site for ritual bathing. In Hindu belief the site is held to be a triple confluence, the third river being the metaphysical Sarasvati. Kuala Lumpur, the capital of Malaysia, is where the Gombak River flows into the Klang River at the site of the Jamek Mosque; the Kolam Biru, a pool with elaborate fountains, has been installed at the apex of the confluence. The Nam Khan River flows into the Mekong at Luang Prabang in Laos; the Jialing flows into the Yangtze at Chongqing in China. The confluence forms a focal point in the city, marked by Chaotianmen Square, built in 1998. In the Far East, the Amur forms the international boundary between Russia; the Ussuri, which demarcates the border, flows into the Amur at a point midway between Fuyuan in China and Khabarovsk in Russia.
The apex of the confluence is located in a rural area, part of China, where a commemorative park, Dongji Square, has been built.
Santa Susana Mountains
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 Valley and Simi Valley on its south from Santa Clara River Valley to the north and Santa Clarita Valley to the northeast; the Oxnard Plain is to the west of Santa Susana Mountains. The Newhall Pass separates the Santa Susana Mountains from the San Gabriel Mountains to the east. Newhall Pass is the major north-south connection between the San Fernando Valley and the Santa Clarita Valley, Interstate 5 and a railroad line share Newhall Pass; the Santa Susana Pass connects the Simi and San Fernando valleys, separates the Santa Susana Mountains from Simi Hills to the south. Santa Susana Pass State Historic Park, is located in the Simi Hills, just south of the Santa Susana Pass, at the northwestern edge of the San Fernando Valley; the Santa Susana Mountains are not as high as the San Gabriel Mountains. The western half of the range lies in Ventura County, the eastern half lies in Los Angeles County.
The southeastern slopes of the Santa Susana Mountains are part of the City of Los Angeles, housing subdivisions, including Porter Ranch, have been built on the lower slopes of the range. The city of Simi Valley lies to the southwest. North of the range is the fast-growing city of Santa Clarita, several large subdivisions in unincorporated Los Angeles County, including Lyons Ranch and Newhall Ranch, have been approved for development; the Sunshine Canyon Landfill is at the mountains' eastern end, several canyons in the northwest corner of the range have been proposed for more landfills. The mountains have a mild climate, with cool, wet winters. Snow melts quickly. Annual Precipitation totals vary between 18 and 25 inches, depending on exposure to the rain-bearing winds. Most of the rain falls between March; because of the summer drought, wildfires sometimes occur in summer and fall before the rains start during hot, dry "Santa Ana" wind events. The highest peaks in the range are Oat Mountain, Mission Point, Rocky Peak, Sand Rock Peak.
The summit of Rocky Peak lies directly atop the line separating Ventura and Los Angeles counties and is indicated by a battered marker imbedded into the sandstone boulder summit. The first discovery of oil in California was in Pico Canyon, on the north side of the mountains, The California Star Oil Works Chevron, succeeded with Pico Well No. 4. It became famous not only as the first well in California, but as the longest-producing well in the world, having been capped in September, 1990 after 114 years. Well No. 4 has the distinction of being the first site in Los Angeles County to be listed on the National Register of Historic Places, in 1966. The surrounding town, Mentryville, is maintained as the oil "ghost town" Mentryville Historical Park, within Pico Canyon Park. Many active oil and gas fields remain in the area, with some of the larger operators including Vintage Production, Freeport McMoRan, the Southern California Gas Company; the largest of SoCalGas's four underground storage natural gas facilities is within the Aliso Canyon Oil Field north of Porter Ranch.
The mountains are within the acquisition area for the Santa Monica Mountains Conservancy, which operates several parks, including Santa Clarita Woodlands Park, Rocky Peak Park, Joughin Open Space Preserve, Happy Camp Canyon Park, other Santa Susana parks in the Santa Susana Mountains through the Mountains Recreation and Conservation Authority. The City of Los Angeles maintains O'Melveny Park at the eastern end of the mountains. Note: the Santa Susana Field Laboratory, once operated by and still owned by Rocketdyne until toxics are cleaned up, is in the Simi Hills, which are adjacent to the south of the Santa Susana Mountains; the south-facing slopes are covered in Chaparral shrubland and oak savanna. The north-facing slopes are home to magnificent oak woodlands and conifer woodlands, some of which have been protected in the Santa Clarita Woodlands Park and other large open space preserves; the mountains are part of the California chaparral and woodlands ecoregion. The oaks, include the evergreen coast live oak, the deciduous valley oak, the coastal scrub oak all can be found in the area.
Spring wildflowers include the redbush monkey flower, Mariposa lily, canyon sunflower. Poison oak is an important member of the native plant habitat community. Various ferns are found in moister and tree-shaded areas. Many bird species thrive in the Santa Susana Mountains; the most common raptors observed soaring over the brushy, boulder-strewn landscape are turkey vultures, red-tailed hawks, American kestrels. In oak woodlands it is not uncommon to see red-shouldered hawks flying from limb to limb. Through the cover of dense, trailside chaparral you might glimpse the California towhee or the colorful spotted towhee, birds who make their presence known by rustling up leaf litter on the ground. California quail, greater roadrunner, common raven are residents of the range; the eerie and enchanting call of the common poorwill can be heard after dark while quick eyes might observe the silent flight of great horned owls and phantom-like barn owls. A handful of fascinating amphibians live in the area.
Streams and creeks support populations of Pacific tree frog, the small amphibian whose signature chorus adds an aura of mystery and inexplicable be
Shrubland, scrub, brush, or bush is a plant community characterised by vegetation dominated by shrubs also including grasses and geophytes. Shrubland may either occur or be the result of human activity, it may be the mature vegetation type in a particular region and remain stable over time, or a transitional community that occurs temporarily as the result of a disturbance, such as fire. A stable state may be maintained by regular natural disturbance such as browsing. Shrubland may be unsuitable for human habitation because of the danger of fire; the term "shrubland" was coined in 1903. Shrubland species show a wide range of adaptations to fire, such as heavy seed production and fire-induced germination. In botany and ecology a shrub is defined as a much-branched woody plant less than 8 m high and with many stems. Tall shrubs are 2–8 m high, small shrubs 1–2 m high and subshrubs less than 1 m high. A descriptive system adopted in Australia to describe different types of vegetation is based on structural characteristics based on plant life-form, plus the height and foliage cover of the tallest stratum or dominant species.
For shrubs 2–8 m high the following structural forms result: dense foliage cover — closed-scrub mid-dense foliage cover — open- sparse foliage cover — tall open shrublandFor shrubs <2 m high the following structural forms result: dense foliage cover — closed-heath mid-dense foliage cover — open-heath sparse foliage cover — low shrubland sparse foliage cover — low open shrubland Similarly, shrubland is a category used to describe a type of biome plant group. In this context, shrublands are dense thickets of evergreen sclerophyll shrubs and small trees, called: Chaparral in California Matorral in Chile and Spain Maquis in France and elsewhere around the Mediterranean Macchia in Italy Fynbos in South Africa Kwongan in Southwest Australia Cedar scrub in Texas Hill CountryIn some places shrubland is the mature vegetation type, in other places the result of degradation of former forest or woodland by logging or overgrazing, or disturbance by major fires. A number of World Wildlife Fund biomes are characterized as shrublands, including: Desert scrublands Xeric or desert scrublands occur in the world's deserts and xeric shrublands ecoregions, or in areas of fast-draining sandy soils in more humid regions.
These scrublands are characterized by plants with adaptations to the dry climate, which include small leaves to limit water loss, thorns to protect them from grazing animals, succulent leaves or stems, storage organs to store water, long taproots to reach groundwater. Mediterranean scrublandsMediterranean scrublands occur in the Mediterranean forests and scrub biomes, located in the five Mediterranean climate regions of the world. Scrublands are most common near the seacoast, have adapted to the wind and salt air of the ocean. Low, soft-leaved scrublands around the Mediterranean Basin are known as garrigue in France, phrygana in Greece, tomillares in Spain, batha in Israel. Northern coastal scrub and coastal sage scrub occur along the California coast, strandveld in the Western Cape of South Africa, coastal matorral in central Chile, sand-heath and kwongan in Southwest Australia. Interior scrublandsInterior scrublands occur in semi-arid areas where soils are nutrient-poor, such as on the matas of Portugal which are underlain by Cambrian and Silurian schists.
Florida scrub is another example of interior scrublands. Dwarf shrubs Some vegetation types are formed of dwarf-shrubs: creeping shrubs; these include the maquis and garrigues of Mediterranean climates, the acid-loving dwarf shrubs of heathland and moorland. Fynbos Maquis Prostrate shrub Semi-desert Shrub-steppe Shrub swamp Moorland
West Hills, Los Angeles
West Hills is a residential and commercial neighborhood in the western San Fernando Valley region of Los Angeles, California. The percentage of residents aged 35 and older is among the highest in Los Angeles County; the neighborhood was the home of many Native American tribes, during the early Spanish and Mexican era was part of the Mission San Fernando Rey de España. In the American era, West Hills was part of Owensmouth, renamed Canoga Park in 1930. West Hills was established in western Canoga Park and retained its present name in 1987. Historic landmarks and many city parks are to be found within the community, as are commercial districts, a business district, religious establishments. Two private high schools are among the 13 schools within West Hills. West Hills is located in the West San Fernando Valley in the county of Los Angeles and about 30 minutes from Downtown Los Angeles, it is off of the 101 Ventura freeway offramp Valley Circle Blvd/Mullholland Highway. According to the Mapping L.
A. project of 2008, the Los Angeles Times, West Hills is flanked on the north by the Chatsworth Reservoir, on the east by Canoga Park, on the south by Woodland Hills, on the southwest by Hidden Hills and on the west by Bell Canyon in Ventura County. In 1987, Los Angeles recognized the following description of the boundaries of West Hills Neighborhood Council: Starting at the centerline intersections of Topanga Canyon Boulevard and Nordhoff Street, westward down the centerline of Nordhoff extended in a straight line to the city limits of the City of Los Angeles. Bell and Dayton creeks in West Hills are several of the headwaters of the Los Angeles River that originate in the Northwest San Fernando Valley; the Los Angeles River itself begins at the confluence of Arroyo Calabasas and Bell Creek in Canoga Park. These and other small creeks supply stormwater and suburban runoff water to the Los Angeles River, several are considered year-round creeks. Although the creeks are now channeled and run within concrete walls, they do form a significant urban wildlife landscape and contribute to the population of indigenous wildlife left within the San Fernando Valley.
Both Bell Creek and Dayton Creek in particular have received attention due to their headwaters origins inside the Santa Susana Field Laboratory in the Simi Hills. The SSFL is mandated for an environmental cleanup due to its uses as a testing center for rocket and missile engines, nuclear reactor research and fuel reprocessing, high technology defense systems, it was the site of a partial nuclear core meltdown in 1959. Prominent contaminants include radionuclides, VOCs-volatile organic compounds, Lead and other components of rocket engine fuel and cleaning compounds; this region experiences warm and dry summers with average temperatures peaking at 96 degree highs throughout August. West Hills has a climate similar to other locations in the west San Fernando Valley, such as nearby Woodland Hills with a long established weather station at Pierce College. According to the Köppen Climate Classification system, West Hills has a warm-summer Mediterranean climate, abbreviated "Csa" on climate maps; as of the 2010 census, according to the Los Angeles Almanac, there were 38,814 people and 10,626 households residing in West Hills.
The ethnic-racial medley of the neighborhood was 96.04% White, 2.04% Asian, 0.05% Pacific Islander, 1.11% African American, 0.36% Native American, 2.80% from other races, 1.82% from two or more races. 3.26% of the population were Hispanic of any race. The Los Angeles Times reported that the 2000 U. S. census counted 30,814 residents in the 8.53-square-mile West Hills neighborhood,—or 4,551 people per square mile, among the lowest population densities for the city. In 2008, the city estimated that the population had increased to 41,426. In 2000 the median age for residents was 39, considered old for county neighborhoods; the neighborhood was considered "moderately diverse" ethnically within Los Angeles, with a high percentage of white residents. The breakdown was whites, 70.9%. Iran and the Philippines were the most common places of birth for the 22.7% of the residents who were born abroad—a low percentage for Los Angeles. The median yearly household income in 2008 dollars was $103,008, considered high for the city and county.
The percentage of households that earned $125,000 and up was high for Los Angeles County. Renters occupied 12.6% of the housing stock, house and condominium-owners occupied 87.4%. The percentages of married people were among the county's highest. In 2000 there were 785 families headed by single parents, a low percentage for both the city and the county. Eleven percent of the population were military veterans, a high rate for the city and the county, the percentages of veterans who served during World War II or the Korean War were among the county's highest; the 1980 census showed 32,370 people living in the area that became West Hills, of whom 92% were white, 7% Hispanic, 1% black, 4% Asian and 3% other. Families constituted 90% of the population, 72% of the residents owned or were
San Fernando Valley
The San Fernando Valley is an urbanized valley in Los Angeles County, California in the Los Angeles metropolitan area, defined by the mountains of the Transverse Ranges circling it. Home to 1.77 million people, it is north of the more populous Los Angeles Basin. Nearly two thirds of the valley's land area is part of the city of Los Angeles; the other incorporated cities in the valley are Glendale, San Fernando, Hidden Hills, Calabasas. The San Fernando Valley is about 260 square miles bound by the Santa Susana Mountains to the northwest, the Simi Hills to the west, the Santa Monica Mountains and Chalk Hills to the south, the Verdugo Mountains to the east, the San Gabriel Mountains to the northeast; the northern Sierra Pelona Mountains, northwestern Topatopa Mountains, southern Santa Ana Mountains, Downtown Los Angeles skyscrapers can be seen from higher neighborhoods and parks in the San Fernando Valley. The Los Angeles River begins at the confluence of Calabasas Creek and Bell Creek, between Canoga Park High School and Owensmouth Ave. in Canoga Park.
These creeks' headwaters are in the Santa Monica Calabasas foothills, the Simi Hills' Hidden Hills, Santa Susana Field Laboratory, Santa Susana Pass Park lands. The river flows eastward along the southern regions of the Valley. One of the river's two unpaved sections can be found at the Sepulveda Basin. A seasonal river, the Tujunga Wash, drains much of the western facing San Gabriel Mountains and passes into and through the Hansen Dam Recreation Center in Lake View Terrace, it flows south along the Verdugo Mountains through the eastern communities of the valley to join the Los Angeles River in Studio City. Other notable tributaries of the river include Dayton Creek, Caballero Creek, Bull Creek, Pacoima Wash, Verdugo Wash; the elevation of the floor of the valley varies from about 600 ft to 1,200 ft above sea level. Most of the San Fernando Valley is within the jurisdiction of the city of Los Angeles, although a few other incorporated cities are located within the valley as well: Burbank and Glendale are in the southeastern corner of the valley, Hidden Hills and Calabasas are in the southwestern corner, San Fernando, surrounded by Los Angeles, is in the northeastern valley.
Universal City, an enclave in the southern part of the valley, is unincorporated land housing the Universal Studios filming lot and theme park. Mulholland Drive, which runs along the ridgeline of the Santa Monica Mountains, marks the boundary between the valley and the communities of Hollywood and the Los Angeles Westside; the valley's natural habitat is a "temperate grasslands and shrublands biome" of grassland, oak savanna, chaparral shrub forest types of plant community habitats, along with lush riparian plants along the river and springs. In this Mediterranean climate, post-1790s European agriculture for the mission's support consisted of grapes, figs and general garden crops; the San Fernando Valley contains five incorporated cities—Glendale, San Fernando, Hidden Hills, Calabasas—and part of a sixth, Los Angeles, which governs a majority of the valley. The unincorporated communities are governed by the County of Los Angeles; the Los Angeles city section of the valley is divided into seven city council districts: 2, 3, 4, 5, 6, 7, 12.
Of the 95 neighborhood councils in the city, 34 are in the valley. The valley is represented in the California State Legislature by seven members of the State Assembly and five members of the State Senate; the valley falls into four congressional districts: the 28th, 29th, 30th, 33rd, represented by Adam Schiff, Tony Cárdenas, Brad Sherman, Ted Lieu. In the Los Angeles County board of supervisors, it is represented by two supervisorial districts, with the western portion represented by Sheila Kuehl and the eastern portion by Kathryn Barger; the San Fernando Valley, for the most part, tends to support Democrats in state and national elections. This is true in the southern areas, which include Sherman Oaks and the city of Burbank; the Los Angeles satellite administrative center for the valley, The Civic Center Van Nuys, is in Van Nuys. The area in and around the Van Nuys branch of Los Angeles City Hall is home to a police station and superior courts and Los Angeles city and county administrative offices.
Northridge is home to Northridge. Many branches of the Los Angeles Public Library are located in the valley. For independent libraries see "Incorporated Cities" in the "Municipalities and districts" list below. Los Angeles Police Department, Los Angeles County Sheriff's Department, independent valley city departments. Los Angeles Fire Department, Los Angeles County Fire Department, Burbank Police Department, independent valley city departments. City of Los Angeles neighborhood councils The Tongva known as the Gabrieleño Mission Indians after colonization, the Tataviam to the north and Chumash to the west, had lived and thrived in the valley and its arroyos for over 8,000 years, they had numerous settlements, trading and hunting camps, before the Spanish arrived in 1769 to settle in the Valley. The first Spanish land grant in the San Fernando Valley was called "Rancho Encino", in the northern part of the San Fernando Valley. Juan Francisco Reyes built an adobe dwelling beside a Tongva village or rancheria at natural springs, but the land was soon taken from him so that a mission could be built there