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49-545: Arastradero Preserve consists of rolling savanna grassland hills and evergreen forests ; the preserve varies in elevation from 275 feet (84 m) in the northeast to 775 feet (236 m) in the southwest. There are four gates (labeled A, B, C, and D) into the preserve, though public parking is available only at Gate A on the North side. Gate D connects to Foothills Park as part of the Bay-to-Ridge Trail. The park

98-569: A collaborative stewardship program on the preserve in cooperation with the City of Palo Alto since 1997. Volunteers and Grassroots Ecology staff work to improve the Preserve by eliminating invasive weeds such as non-native thistles, planting native species such as blue wild rye and engaging local youth and community members. Portions of Arastradero Preserve border Foothills Park (on the South side),

147-438: A continuous tree canopy which would prevent further grass growth. Prior to European settlement aboriginal land use practices, including fire, influenced vegetation and may have maintained and modified savanna flora. It has been suggested by many authors that aboriginal burning created a structurally more open savanna landscape. Aboriginal burning certainly created a habitat mosaic that probably increased biodiversity and changed

196-491: A dramatic reduction in basal area and canopy cover, often leaves a high percentage of woody plants alive either as seedlings too small to be affected or as plants capable of re-sprouting from lignotubers and broken stumps. A population of woody plants equal to half or more of the original number often remains following pulling of eucalypt communities, even if all the trees over 5 metres are uprooted completely. A number of exotic plants species have been introduced to savannas around

245-804: A high tree density. It is often believed that savannas feature widely spaced, scattered trees. However, in many savannas, tree densities are higher and trees are more regularly spaced than in forests. The South American savanna types cerrado sensu stricto and cerrado dense typically have densities of trees similar to or higher than that found in South American tropical forests, with savanna ranging from 800 to 3300 trees per hectare (trees/ha) and adjacent forests with 800–2000 trees/ha. Similarly Guinean savanna has 129 trees/ha, compared to 103 for riparian forest , while Eastern Australian sclerophyll forests have average tree densities of approximately 100 per hectare , comparable to savannas in

294-531: A light canopy . Woodlands may support an understory of shrubs and herbaceous plants including grasses . Woodland may form a transition to shrubland under drier conditions or during early stages of primary or secondary succession . Higher-density areas of trees with a largely closed canopy that provides extensive and nearly continuous shade are often referred to as forests . Extensive efforts by conservationist groups have been made to preserve woodlands from urbanization and agriculture . For example,

343-402: A means of clearing land. In the 1950s arboricides suitable for stem injection were developed. War-surplus heavy machinery was made available, and these were used for either pushing timber, or for pulling using a chain and ball strung between two machines. These two new methods of timber control, along with the introduction and widespread adoption of several new pasture grasses and legumes promoted

392-419: A miniature scale model of the park and exhibits explaining the ecology, flora, and fauna of the region. 37°23′13″N 122°10′29″W  /  37.38694°N 122.17472°W  / 37.38694; -122.17472 Savanna A savanna or savannah is a mixed woodland - grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that

441-444: A reduction in the need to burn to produce a flush of green growth because legumes retain high nutrient levels throughout the year, and because fires can have a negative impact on legume populations which causes a reluctance to burn. The closed forest types such as broadleaf forests and rainforests are usually not grazed owing to the closed structure precluding grass growth, and hence offering little opportunity for grazing. In contrast

490-444: A result of global climate change, particularly at ecotones such as savannas so often represent. A savanna can simply be distinguished by the open savanna, where grass prevails and trees are rare; and the wooded savanna, where the trees are densest, bordering an open woodland or forest. Specific savanna ecoregions of several different types include: Woodland A woodland ( / ˈ w ʊ d l ə n d / ) is, in

539-469: A resurgence in tree clearing. The 1980s also saw the release of soil-applied arboricides, notably tebuthiuron , that could be utilised without cutting and injecting each individual tree. In many ways "artificial" clearing, particularly pulling, mimics the effects of fire and, in savannas adapted to regeneration after fire as most Queensland savannas are, there is a similar response to that after fire. Tree clearing in many savanna communities, although causing

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588-459: A simplified yet widespread climatic concept. The divergence has sometimes caused areas such as extensive savannas north and south of the Congo and Amazon Rivers to be excluded from mapped savanna categories. In different parts of North America, the word "savanna" has been used interchangeably with " barrens ", " prairie ", " glade ", "grassland" and " oak opening ". Different authors have defined

637-502: Is also about 0.2 miles from the Paseo del Roble entrance. The southwest portion of the preserve protects seasonal Felt Creek, which runs beneath Arastradero Road and is diverted to Felt Lake . In wet years, Felt Lake releases flows which reach Los Trancos Creek , a San Francisquito Creek tributary. The preserve contains an abundance of wildlife, including deer , bobcats , coyotes , snakes , and many species of birds . The preserve and

686-463: Is also accessible from a pedestrian footpath that leads to the residential area on the street Paseo del Roble. The east portion of the preserve protects Arastradero Creek , which flows into Matadero Creek at the junction of Arastradero Road and Page Mill Road. Near the East side about a quarter mile south of the entrance is Arastradero Lake, and further south up into the preserve is Sobey Pond. The lake

735-483: Is not prominent but that rivers in savanna landscapes erode more by lateral migration . Flooding and associated sheet wash have been proposed as dominant erosion processes in savanna plains. The savannas of tropical America comprise broadleaved trees such as Curatella , Byrsonima , and Bowdichia , with grasses such as Leersia and Paspalum . Bean relative Prosopis is common in the Argentinian savannas. In

784-473: Is possible for there to be multiple stable biomes. The annual rainfall ranges from 500 mm (19.69 in) to 1,270 mm (50.00 in) per year, with the precipitation being more common in six or eight months of the year, followed by a period of drought. Savannas may at times be classified as forests. In climatic geomorphology it has been noted that many savannas occur in areas of pediplains and inselbergs . It has been posited that river incision

833-635: Is used in British nature conservation to refer to any wooded land that has existed since 1600, and often (though not always) for thousands of years, since the last Ice Age (equivalent to the American term old-growth forest ) Woodlot is a closely related term in American forest management , which refers to a stand of trees generally used for firewood. While woodlots often technically have closed canopies, they are so small that light penetration from

882-419: Is vague and therefore the two can be combined into a single biome as both woodlands and savannas feature open-canopied trees with crowns not usually interlinking (mostly forming 25-60% cover). Over many large tropical areas, the dominant biome (forest, savanna or grassland) can not be predicted only by the climate, as historical events plays also a key role, for example, fire activity. In some areas, indeed, it

931-462: The Mediterranean region were likewise created and maintained by anthropogenic fire. Intentional controlled burns typically create fires confined to the herbaceous layer that do little long term damage to mature trees. This prevents more catastrophic wildfires that could do much more damage. However, these fires either kill or suppress tree seedlings, thus preventing the establishment of

980-455: The canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Four savanna forms exist; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent. Savannas maintain an open canopy despite

1029-476: The greenhouse effect may result in an alteration of the structure and function of savannas. Some authors have suggested that savannas and grasslands may become even more susceptible to woody plant encroachment as a result of greenhouse induced climate change . However, a recent case described a savanna increasing its range at the expense of forest in response to climate variation, and potential exists for similar rapid, dramatic shifts in vegetation distribution as

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1078-749: The prairies in North America and steppes in Eurasia , which feature cold winters, savannas are mostly located in areas having warm to hot climates, such as in Africa, Australia, Thailand, South America and India. The word derives from the Spanish sabana , which is itself a loanword from Taíno , which means "treeless grassland" in the West Indies . The letter b in Spanish, when positioned in

1127-554: The Australian savanna, mammals in the family Macropodidae predominate, such as kangaroos and wallabies, though cattle, horses, camels, donkeys and the Asian water buffalo , among others, have been introduced by humans. It is estimated that less than three percent of savanna ecosystems can be classified as highly intact. Reasons for savanna degradation are manifold, as outlined below. Savannas are subject to regular wildfires and

1176-505: The East African savannas, Acacia , Combretum , baobabs , Borassus , and Euphorbia are a common vegetation genera. Drier savannas there feature spiny shrubs and grasses, such as Andropogon , Hyparrhenia , and Themeda . Wetter savannas include Brachystegia trees and Pennisetum purpureum , and elephant grass type. West African savanna trees include Anogeissus , Combretum , and Strychnos . Indian savannas are mostly cleared, but

1225-527: The Northern Territory, Australia savanna, and 480,000 ha of savanna were being cleared annually in Queensland in the 2000s, primarily to improve pasture production. Substantial savanna areas have been cleared of woody vegetation and much of the area that remains today is vegetation that has been disturbed by either clearing or thinning at some point in the past. Clearing is carried out by

1274-700: The Palo Alto Golf Course (on the East side), open land owned by Stanford University (to the North), and one of the campuses of Palo Alto University (to the West). From the hills on the North Side, one can see Felt Lake which is otherwise difficult to see from public lands except Vista Hill in Foothills Park. Because most of the golf course in on a flat mesa at a higher elevation than the preserve,

1323-448: The broad sense, land covered with woody plants ( trees and shrubs ), or in a narrow sense, synonymous with wood (or in the U.S., the plurale tantum woods ), a low-density forest forming open habitats with plenty of sunlight and limited shade (see differences between British , American and Australian English explained below). Some savannas may also be woodlands, such as savanna woodland , where trees and shrubs form

1372-415: The court of the cacique Carlos in present-day Panama . The accounts are inexact, but this is usually placed in present-day Madugandí or at points on the nearby Guna Yala coast opposite Ustupo or on Point Mosquitos . These areas are now either given over to modern cropland or jungle . Many grassy landscapes and mixed communities of trees, shrubs, and grasses were described as savanna before

1421-566: The ecosystem appears to be the result of human use of fire. For example, Native Americans created the Pre-Columbian woodlands of North America by periodically burning where fire-resistant plants were the dominant species. Aboriginal burning appears to have been responsible for the widespread occurrence of savanna in tropical Australia and New Guinea , and savannas in India are a result of human fire use. The maquis shrub savannas of

1470-417: The edge makes them ecologically closer to woodland than forest. North American forests vary widely in their ecology and are greatly dependent on abiotic factors such as climate and elevation. Much of the old-growth deciduous and pine-dominated forests of the eastern United States was harvested for lumber, paper pulp, telephone poles, creosote, pitch, and tar. In Australia, a woodland is defined as an area with

1519-467: The establishment, growth and survival of plant species and in turn can lead to a change in woodland structure and composition. That being said, impact of grazing animals can be reduced. Looking at Elephant impact on Savannas, the overall impact is reduced in the presence of rainfall and fences. Large areas of Australian and South American savannas have been cleared of trees, and this clearing continues today. For example, land clearing and fracking threaten

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1568-405: The golf course is largely invisible from the preserve. There remains a small piece of private property adjacent to Arastradero Road surrounded on all sides by the preserve which currently has no structures. There had been a private home deep within the preserve until the late 1990s which has now been torn down. In 2006 a small visitor center was erected near the parking lot entrance which contains

1617-483: The grazing industry in an attempt to increase the quality and quantity of feed available for stock and to improve the management of livestock. The removal of trees from savanna land removes the competition for water from the grasses present, and can lead to a two to fourfold increase in pasture production, as well as improving the quality of the feed available. Since stock carrying capacity is strongly correlated with herbage yield, there can be major financial benefits from

1666-568: The lower limits of savanna tree coverage as 5–10% and upper limits range as 25–80% of an area. Two factors common to all savanna environments are rainfall variations from year to year, and dry season wildfires . In the Americas , e.g. in Belize , Central America , savanna vegetation is similar from Mexico to South America and to the Caribbean . The distinction between woodland and savanna

1715-465: The middle of a word, is pronounced almost like an English v; hence the change of grapheme when transcribed into English. The word originally entered English as the Zauana in a description of the ilands of the kinges of Spayne from 1555. This was equivalent in the orthography of the times to zavana (see history of V ). Peter Martyr reported it as the local name for the plain around Comagre,

1764-425: The middle of the 19th century, when the concept of a tropical savanna climate became established. The Köppen climate classification system was strongly influenced by effects of temperature and precipitation upon tree growth, and oversimplified assumptions resulted in a tropical savanna classification concept which considered it as a "climatic climax" formation. The common usage to describe vegetation now conflicts with

1813-469: The open structure of savannas allows the growth of a herbaceous layer and is commonly used for grazing domestic livestock. As a result, much of the world's savannas have undergone change as a result of grazing by sheep, goats and cattle, ranging from changes in pasture composition to woody plant encroachment . The removal of grass by grazing affects the woody plant component of woodland systems in two major ways. Grasses compete with woody plants for water in

1862-438: The potential to significantly alter the structure and composition of savannas worldwide, and have already done so in many areas through a number of processes including altering the fire regime, increasing grazing pressure, competing with native vegetation and occupying previously vacant ecological niches. Other plant species include: white sage, spotted cactus, cotton seed, rosemary. Human induced climate change resulting from

1911-431: The removal of trees, such as assisting with grazing management: regions of dense tree and shrub cover harbors predators, leading to increased stock losses, for example, while woody plant cover hinders mustering in both sheep and cattle areas. A number of techniques have been employed to clear or kill woody plants in savannas. Early pastoralists used felling and girdling , the removal of a ring of bark and sapwood , as

1960-585: The reserved ones feature Acacia, Mimosa , and Zizyphus over a grass cover comprising Sehima and Dichanthium . The Australian savanna is abundant with sclerophyllous evergreen vegetation, which include the eucalyptus , as well as Acacia, Bauhinia , Pandanus with grasses such as Heteropogon and kangaroo grass (Themeda). Animals in the African savanna generally include the giraffe, elephant, buffalo, zebra, gnu, hippopotamus, rhinoceros, and antelope, where they rely on grass and/or tree foliage to survive. In

2009-453: The same region. Savannas are also characterised by seasonal water availability, with the majority of rainfall confined to one season. They are associated with several types of biomes , and are frequently in a transitional zone between forest and desert or grassland , though mostly a transition between desert to forest. Savanna covers approximately 20% of the Earth's land area. Unlike

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2058-515: The soil caused by the hooves of animals and through the erosion effects caused by the removal of protective plant cover. Such effects are most likely to occur on land subjected to repeated and heavy grazing. The effects of overstocking are often worst on soils of low fertility and in low rainfall areas below 500 mm, as most soil nutrients in these areas tend to be concentrated in the surface so any movement of soils can lead to severe degradation. Alteration in soil structure and nutrient levels affects

2107-606: The spread of weeds in savannas by the removal or reduction of the plants which would normally compete with potential weeds and hinder establishment. In addition to this, cattle and horses are implicated in the spread of the seeds of weed species such as prickly acacia ( Acacia nilotica ) and stylo ( Stylosanthes species). Alterations in savanna species composition brought about by grazing can alter ecosystem function, and are exacerbated by overgrazing and poor land management practices. Introduced grazing animals can also affect soil condition through physical compaction and break-up of

2156-519: The structure of woodlands and geographic range of numerous woodland species. It has been suggested by many authors that with the removal or alteration of traditional burning regimes many savannas are being replaced by forest and shrub thickets with little herbaceous layer. The consumption of herbage by introduced grazers in savanna woodlands has led to a reduction in the amount of fuel available for burning and resulted in fewer and cooler fires. The introduction of exotic pasture legumes has also led to

2205-596: The surrounding area are habitats for the California puma ( Puma concolor is also locally known as mountain lion). There are regular sightings of puma and coyotes in the areas, and people hiking with dogs or small children should be cautious. From 2016 through 2020, a pair of bald eagles ( Haliaeetus leucocephalus ) has nested in a large eucalyptus tree near Felt Lake and the preserve. The Pearson–Arastradero Preserve has 10.25 miles (16.50 km) of trails for hiking , biking and horseback riding . While many of

2254-463: The topsoil and removal by grazing reduces this competitive effect, potentially boosting tree growth. In addition to this effect, the removal of fuel reduces both the intensity and the frequency of fires which may control woody plant species. Grazing animals can have a more direct effect on woody plants by the browsing of palatable woody species. There is evidence that unpalatable woody plants have increased under grazing in savannas. Grazing also promotes

2303-424: The trails are open year-round, some trails are designated as "seasonal" and are closed at the trailhead temporarily after heavy rain . The trails at Arastradero Preserve include Acorn, Arastradeo Creek, Bay Laurel, Bowl Loop, Juan Bautista de Anza, Meadowlark, Ohlone, Paseo del Roble, Portola Pastures, Redtail Loop, Wild Rye, Woodland Star, and Woodrat. Grassroots Ecology , a local environmental nonprofit, has run

2352-646: The woodlands of Northwest Indiana have been preserved as part of the Indiana Dunes . Woodland is used in British woodland management to mean tree-covered areas which arose naturally and which are then managed. At the same time, forest is usually used in the British Isles to describe plantations , usually more extensive, or hunting Forests , which are a land use with a legal definition and may not be wooded at all. The term ancient woodland

2401-665: The world. Amongst the woody plant species are serious environmental weeds such as Prickly Acacia ( Acacia nilotica ), Rubbervine ( Cryptostegia grandiflora ), Mesquite ( Prosopis spp.), Lantana ( Lantana camara and L. montevidensis ) and Prickly Pear ( Opuntia spp.). A range of herbaceous species have also been introduced to these woodlands, either deliberately or accidentally including Rhodes grass and other Chloris species, Buffel grass ( Cenchrus ciliaris ), Giant rat's tail grass ( Sporobolus pyramidalis ) parthenium ( Parthenium hysterophorus ) and stylos ( Stylosanthes spp.) and other legumes . These introductions have

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