Quercus humboldtii
Quercus humboldtii known as the Andean oak, Colombian oak or roble, is a species of oak in the beech family found only in Colombia and Panamá. It is named for Alexander von Humboldt, it grows in the mountains with an altitudinal range from 1,000 to 3,200 m. It is found on all some lowland inter-Andean regions. Quercus humboldtii is an evergreen tree which grows to a height of 25 meters and a diameter of 1 meter, with buttresses of up to 1 meter, its bark is reddish grey and fissured, breaking into squares and flaking. The leaves simple and lanceolate, up to 10–20 cm long, clustered at the ends of the branches; the flowers are small and unisexual, with a racemic inflorescence. Male flowers are numerous, with long-styled female flowers in a cupula; the fruit is a light brown, ovoid capsule, or acorn, with a leathery pericarp, 20–25 mm in diameter and 50–70 mm long, resting on a scaly cupule. Only one fruit per cupule is developed, the inside of the acorn shell is woolly; the tree grows in the Andean highlands where the mean annual temperature is 16−24 °C, the mean annual rainfall 1500–2500 mm.
It can be found in moderately fertile and deep soils as well as in degraded soils, preferring shallow soils with a thick layer of humus. The acorns provide important food for wildlife.
Quercus turbinella
Quercus turbinella is a North American species of oak known by the common names shrub oak, turbinella oak, shrub live oak, gray oak. It is native to Arizona, New Mexico, Utah and Nevada in the western United States, it occurs in northern Mexico. Quercus turbinella has been found in Arizona, New Mexico, Utah, southern California, western Texas, Baja California. In California it occurs in a few eastern California desert ranges; the populations on the desert mountains in the western Mojave desert and the inner coastal ranges are now considered Quercus john-tuckeri. It grows in woodland, chaparral and other habitat, it is most common in chaparral habitat in central Arizona, through the transition zone of the Mogollon Rim–White Mountains, but southeast Arizona in the Madrean Sky Island mountain ranges of sky islands. Quercus turbinella is a shrub growing 2–5 meters in height but sometimes becoming treelike and exceeding 6 meters; the branches are gray or brown, the twigs coated in short woolly fibers when young and becoming scaly with age.
The thick, leathery evergreen leaves are up to 3 centimeters long by 2 cm wide and are edged with large, spine-tipped teeth. They are gray-green to yellowish in color and waxy in texture on the upper surfaces, yellowish and hairy or woolly and glandular on the lower surfaces; the males catkins are yellowish-green and the female flowers are in short spikes in the leaf axils, appearing at the same time as the new growth of leaves. The fruit is a yellowish brown acorn up to two centimeters long with a shallow warty cup about a centimeter wide; this oak reproduces sexually via its acorns if there is enough moisture present, but more it reproduces vegetatively by sprouting from its rhizome and root crown. Quercus turbinella hybridizes with other oak species, including Quercus gambelii, Quercus havardii, Quercus arizonica, Q. grisea. Many species of animals use it for food, with wild and domesticated ungulates browsing the foliage and many birds and mammals eating the acorns. Animals use the shrub as cover, mountain lions hide their kills in the thickets.
Jepson eFlora, The Jepson Herbarium, University of California, Berkeley Flora of North America.
Grove (nature)
A grove is a small group of trees with minimal or no undergrowth, such as a sequoia grove, or a small orchard planted for the cultivation of fruits or nuts. Other words for groups of trees include woodland, thicket, or stand; the main meaning of "grove" is a group of trees that grow close together without many bushes or other plants underneath. It is an old word in English, with records of its use dating as far back as 1,000 years ago, although the word's true origins are unknown. Naturally-occurring groves are small a few acres at most. Orchards, by contrast, may be small or large, like the apple orchards in Washington state, orange groves in Florida. Groves were considered sacred in pagan, pre-Christian Germanic and Celtic cultures. Helen F. Leslie-Jacobsen argues that "we can assume that sacred groves existed due to repeated mentions in historiographical and ethnographical accounts. E.g. Tacitus, Germania." Bosquet is an artificial grove in a french formal garden The National Grove of State Trees at the United States National Arboretum Sacred grove "Start Now to Design Citrus Groves for Mechanical Harvesting".
University of Florida, Institute of Food and Agricultural Sciences. Retrieved 2006-01-06
Quercus coccifera
Quercus coccifera, the kermes oak, is an oak tree in the Quercus section Cerris. It is native to the Mediterranean region and Northern African Maghreb, south to north from Morocco to France and west to east from Portugal to Cyprus and Turkey, crossing Spain, Libya and Greece, including Crete; the Kermes Oak was important as the food plant of the Kermes scale insect, from which a red dye called crimson was obtained. The etymology of the specific name coccifera is related to the production of red cochineal dye and derived from Latin coccum, from Greek κόκκος, the kermes insect; the Latin -fera means'bearer'. Quercus coccifera is a shrub less than 2 metres high a small tree, reaching 1–6 metres tall and 50 cm trunk diameter, it is evergreen, with spiny-serrated coriaceous leaves 1.5 -- 1 -- 3 cm broad. The acorns are 2 -- 3 cm long and 1.5 -- 2 cm diameter. They are held in a cup covered in dense, reflexed scales; the kermes oak is a scrub oak related to the Palestine oak of the eastern Mediterranean, with some botanists including the latter in kermes oak as a subspecies or variety.
The Palestine oak is distinguished from it by larger acorns over 2 cm diameter. It is associated with several asparagus species, Crataegus monogyna, Mediterranean dwarf palm, myrtle, several species of Junipers, Pistacia terebinthus, wild Olea europea, Rhamnus atlantica, Rhamnus lycioides, Rhamnus oleoides, Rhamnus catharticus etc; the communities receiving several characteristic names. It is indifferent to chemistry of soils, living on calcareous, pebbly and poor soils. A lover of warm weather, it starts to fail from 1000 metres above sea level, it is capable of supporting the continental Mediterranean climate with extreme temperatures and low rainfall, replacing Quercus ilex in drier areas where it excels in drought resistance. It grows on sea cliffs and in windy areas where other species of Quercus or Pinus cannot resist the harsh weather conditions. Kermes oak species grow in sunny slopes. Quercus coccifera supports either drought summers and semi-desert climate with rainfall between 400 and 600mm, with a maximum in the fall and spring.
In its habitat summers are hot and winters are cold with the dry summer season with more than 35 °C reaching over 40 °C. In winter the temperatures drop below 0 °C, it lives in areas with moisture produced by condensation fogs, many Ground frost on clear nights and sporadic snowfalls. A hardy species, it grows well in all types of soils as a shrub, withstanding overgrazing, it blooms from March to May in weather still wet. It is propagated by seed, an acorn that lies dormant until germinated by wet weather; this might occur anywhere from late summer to late autumn or early winter of the following year. The acorns are bitter, varying in size and shape from one specimen to another and tasting bad. Acorns can germinate before falling from the plant, but Quercus coccifera is multiplied by root suckers and layering. Kermes oaks have become scarce, due to their replacement in wet zones by larger species such as Holm oak, it has suffered from extensive culling for use as charcoal. It is the only food and shelter for wildlife in some areas, such as the Ebro valley and other dry areas where chaparral replaces oaks due to low rainfall.
Populations occur in desert regions without any inhabited nucleus because crops are not economically profitable and the climate becomes progressively more continental and drier and therefore end in extreme temperatures accompanied by slow-growing dwarf juniper species. It is the last species of genus Quercus to disappear, their ecological importance is as a habitat and food source in these areas for nesting birds, foxes and wild boars. It forms thickets and dense, some recorded as tall as five meters, it is sometimes accompanied by other plant species of the same size and climber plants such as asparagus or zarzaparrilla. It is an important Mediterranean bush or dwarf vegetation, where the biome it dominates bears its name. Q. coccifera form monospecific communities or communities integrated with Pinus, mediterranean buckthorns, Arecaceae, Pistacia, Thymus, etc. It is located throughout the region around the Mediterranean Sea in central southern and eastern halves, but is always missing from elevated and inland areas, with the exception of the semi-arid interior of the Ebro Valley where it is the dominant species.
It is found on islands in the Mediterranean, from the Balearic Islands to Cyprus. It is common in Crete and can survive heavy sheep and goat grazing for long periods as a ground cover a few centimeters high; the same is true in Mallorca and the Iberian peninsula. It is included as an endangered species in the Red Book of Bulgaria, it is called "chêne des garrigues" in French. The term "garrigue" comes from Catalan or Occitan "garric" the name for Q. coccifera in those languages. The common Spanish name of Q. coccifera is chaparro, which refers to its small size, a feature it shares with other oak species in similar habitats in other parts of the world, such as the chaparral communities from various parts of the Americas. The word chaparro comes from the Basque txapar meaning "little thic
Quercus minima
Quercus minima, the dwarf live oak or minimal oak, is a North American species of shrubs in the beech family. It is native to the southeastern United States. Quercus minima is an evergreen or semi-evergreen shrub more than 2 meters tall, reproducing by seed and by means of underground rhizomes, it forms extensive cloned colonies with many stems, many of them unbranched. Leaves are alternate, up to 12 cm long, toothless or with irregular teeth or lobes. Lobes, when present, are spine-tipped. Leaves are retained through the winter, dropping just before or as new growth resumes in late winter or early spring. Quercus minima is native to the coastal plain of the southeastern United States in Florida but extending from there to the Carolinas and eastern Louisiana. There are reports of the species growing in Texas, but these populations appear to belong to other taxa.)
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance; the reference substance for liquids is nearly always water at its densest. Nonetheless, the temperature and pressure must be specified for the reference. Pressure is nearly always 1 atm. Temperatures for both sample and reference vary from industry to industry. In British beer brewing, the practice for specific gravity as specified above is to multiply it by 1,000. Specific gravity is used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as brines, antifreeze coolants, sugar solutions and acids. Being a ratio of densities, specific gravity is a dimensionless quantity; the reason for the specific gravity being dimensionless is to provide a global consistency between the U. S. and Metric Systems, since various units for density may be used such as pounds per cubic feet or grams per cubic centimeter, etc.
Specific gravity varies with pressure. Substances with a specific gravity of 1 are neutrally buoyant in water; those with SG greater than 1 are denser than water and will, disregarding surface tension effects, sink in it. Those with an SG less than 1 will float on it. In scientific work, the relationship of mass to volume is expressed directly in terms of the density of the substance under study, it is in industry where specific gravity finds wide application for historical reasons. True specific gravity can be expressed mathematically as: S G true = ρ sample ρ H 2 O where ρsample is the density of the sample and ρH2O is the density of water; the apparent specific gravity is the ratio of the weights of equal volumes of sample and water in air: S G apparent = W A, sample W A, H 2 O where WA,sample represents the weight of the sample measured in air and WA,H2O the weight of water measured in air. It can be shown that true specific gravity can be computed from different properties: S G true = ρ sample ρ H 2 O = m sample V m H 2 O V = m sample m H 2 O g g = W V, sample W V, H 2 O where g is the local acceleration due to gravity, V is the volume of the sample and of water, ρsample is the density of the sample, ρH2O is the density of water and WV represents a weight obtained in vacuum.
The density of water varies with pressure as does the density of the sample. So it is necessary to specify the temperatures and pressures at which the densities or weights were determined, it is nearly always the case. But as specific gravity refers to incompressible aqueous solutions or other incompressible substances, variations in density caused by pressure are neglected at least where apparent specific gravity is being measured. For true specific gravity calculations, air pressure must be considered. Temperatures are specified by the notation, with Ts representing the temperature at which the sample's density was determined and Tr the temperature at which the reference density is specified. For example, SG would be understood to mean that the density of the sample was determined at 20 °C and of the water at 4 °C. Taking into account different sample and reference temperatures, we note that, while SGH2O = 1.000000, it is the case that SGH2O = 0.998203⁄0.999840 = 0.998363. Here, temperature is being specified using the current ITS-90 scale and the densities used here and in the rest of this article are based on that scale.
On the previous IPTS-68 scale, the densities at 20 °C and 4 °C are 0.9982071 and 0.9999720 respective
Quercus ilex
Quercus ilex, the evergreen oak, holly oak or holm oak, is a large evergreen oak native to the Mediterranean region. It takes its name from an ancient name for holly, it is a member of the Cerris section of the genus, with acorns. The first trees to be grown from acorns in England are still to be found within the stately grounds of Mamhead Park, Devon. From Britton & Brayley The Beauties of England and Wales: "The woods and plantations of Mamhead are numerous and extensive. Many of them were introduced by Mr Thomas Balle, the last of that family who, on returning from the continent brought with him a quantity of cork, wainscot, oak; the resemblance of the foliage to that of the common European holly, Ilex aquifolium, has led to its common and botanic names. The name ilex was the classical Latin name for the holm oak, but adopted as a botanical genus name for the hollies. An evergreen tree of large size, attaining in favourable places a height of 21–28 m, developing in open situations a huge head of densely leafy branches as much across, the terminal portions of the branches pendulous in old trees.
The trunk is sometimes over 6 m in girth. The young shoots are clothed with a close grey felt; the leaves are variable in shape, most narrowly oval or ovate-lanceolate, 4–8 cm long, 1.2–2.5 cm wide, rounded or broadly tapered at the base, the margins sometimes entire, sometimes more or less remotely toothed. When quite young, both surfaces are clothed with whitish down, which soon falls away from the upper surface leaving it a dark glossy green. Fruits are produced one to three together on a short downy stalk. There are two subspecies: Quercus ilex subsp. Ilex. Native in the north and east of the species' range, from northern Iberia and France east to Greece. Leaves narrow. Quercus ilex subsp. Rotundifolia. Native in the southwest of the species' range, in central and southern Iberia and northwest Africa. Leaves broader. Holm oak grows in pure stands or mixed forest in the Mediterranean and at low or moderate elevations. One of the plant associations in which holm oak is found is the holm oak/Atlas cedar forests of the Atlas Mountains.
In Morocco, some of these mixed forests are habitat to the endangered primate, Barbary macaque, Macaca sylvanus. Holm oak is prevalent from Portugal to Greece along the northern Mediterranean coastal belt, from Morocco to Tunisia along the southern Mediterranean coast. Holm oak is listed as an alien invader; the tree is unable to withstand severe frost, which would prevent it from spreading north, but with climate change, it has penetrated these areas. The largest population of Holm oak in Northern Europe is present on and around St. Boniface Down on the Isle of Wight and into the neighbouring town of Ventnor, has shown to tolerate the high winds on the downs, it is thought that this population's propagation has been bolstered by native Eurasian jays, which harvest acorns from oak trees and store them by burying them in the ground where they may germinate. The wood is hard and tough, has been used since ancient times for general construction purposes as pillars, wagons and wine casks, it is used as firewood and in charcoal manufacture.
The holm oak is one of the top three trees used in the establishment of truffle orchards, or truffières. Truffles grow in an ectomycorrhizal association with the tree's roots; the acorns, like those of the cork oak, are edible and are an important food for free-range pigs reared for ibérico ham production. Boiled in water, the acorns can be used as a medicinal treatment for wound disinfections. Q. ilex can be clipped to form a tall hedge, it is suitable for coastal windbreaks, in any well drained soil. It forms a picturesque rounded head, with pendulous low-hanging branches, its size and solid evergreen character gives it an imposing architectural presence that makes it valuable in many urban and garden settings. While holm oak can be grown in much of maritime northwestern Europe, it is not tolerant of cold continental winters; the TROBI Champion in Gloucestershire measured 27 1⁄4 ft in circumference at 1.2 m height in 1993. Another tree at Courtown House, Ireland, reputedly planted in 1648, measured 20 m in height, with a spread of 43 m in 2010.
A specimen in Milo, in Sicily, is reputed to be 700 years old while a small population on the slopes of northern village of Wardija in Malta are said to be between 500 and 1,000 years old. Prior to the Carthaginian period, holm oak was prevalent on the islands. BBC News Holm Oak: Garden Invader Royal Botanic Garden Flora Europaea: Quercus ilex W. J. Bean Trees and shrubs hardy in the British Isles 8th ed. revised. John Murray. C. Michael Hogan Barbary Macaque: Macaca sylvanus, Globaltwitcher.com, ed. N. Strõmberg Holm Oak K. Rushforth Trees of Britain and Europe. HarperCollins ISBN 0-00-220013-9. Chênes: Quercus ilex Quercus ilex - information, genetic conservation units and related resources. European Forest Genetic Resources Programme Media related to
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