Oak
Foliage and acorns of Quercus robur
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Fagales
Family:	Fagaceae
Genus:	Quercus L.
Species
See List of Quercus species

An oak is a tree or shrub in the genus Quercus ( /ˈkwɜrkəs/;^[1] Latin "oak tree"), of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus. The genus is native to the northern hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in Asia and the Americas.

Oaks have spirally arranged leaves, with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. Many deciduous species are marcescent, not dropping dead leaves until spring. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species. The live oaks are distinguished for being evergreen, but are not actually a distinct group and instead are dispersed across the genus.

Classification[link]

Oak trees are a flowering plant. The genus is divided into two subgenera and a number of sections:

[edit] Subgenus Quercus

The Subgenus Quercus is divided into the following sections:

• Sect. Quercus (synonyms Lepidobalanus and Leucobalanus), the white oaks of Europe, Asia and North America. Styles are short; acorns mature in 6 months and taste sweet or slightly bitter; the inside of an acorn shell is hairless. The leaves mostly lack a bristle on their lobe tips, which are usually rounded.
• Sect. Mesobalanus, Hungarian oak and its relatives of Europe and Asia. Styles long; acorns mature in about 6 months and taste bitter; the inside of this acorn's shell is hairless. The section Mesobalanus is closely related to section Quercus and sometimes included in it.
• Sect. Cerris, the Turkey oak and its relatives of Europe and Asia. Styles long; acorn mature in 18 months and taste very bitter. The inside of the acorn's shell is hairless. Its leaves typically have sharp lobe tips, with bristles at the lobe tip.
• Sect. Protobalanus, the Canyon live oak and its relatives, in southwest United States and northwest Mexico. Styles short, acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. Leaves typically have sharp lobe tips, with bristles at the lobe tip.
• Sect. Lobatae (synonym Erythrobalanus), the red oaks of North America, Central America and northern South America. Styles long; acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. The actual nut is encased in a thin, clinging, papery skin. Leaves typically have sharp lobe tips, with spiny bristles at the lobe.

[edit] Subgenus Cyclobalanopsis

• The ring-cupped oaks of eastern and southeastern Asia. Evergreen trees growing 10–40 m tall. They are distinct from subgenus Quercus in that they have acorns with distinctive cups bearing concrescent rings of scales; they commonly also have densely clustered acorns, though this does not apply to all of the species. The Flora of China treats Cyclobalanopsis as a distinct genus, but most taxonomists consider it a subgenus of Quercus. It contains about 150 species. Species of Cyclobalanopsis are common in the evergreen subtropical laurel forests which extend from southern Japan, southern Korea, and Taiwan across southern China and northern Indochina to the eastern Himalayas, in association with trees of genus Castanopsis and the laurel family (Lauraceae).

A hybrid white oak, possibly Quercus stellata × Q. muhlenbergii

Hybridization[link]

Interspecific hybridization is quite common among oaks but usually between species within the same section only and most common in the white oak group (subgenus Quercus, section Quercus; see List of Quercus species). Inter-section hybrids, except between species of sections Quercus and Mesobalanus, are unknown. Recent systematic studies appear to confirm a high tendency of Quercus species to hybridize because of a combination of factors. White oaks are unable to discriminate against pollination by other species in the same section. Because they are wind pollinated and they have weak internal barriers to hybridization, hybridization produces functional seeds and fertile hybrid offspring.^[2] Ecological stresses, especially near habitat margins, can also cause a breakdown of mate recognition as well as a reduction of male function (pollen quantity and quality) in one parent species.^[2][3]

Frequent hybridization among oaks has consequences for oak populations around the world; most notably, hybridization has produced large populations of hybrids with copious amounts of introgression, and the evolution of new species.^[4] Frequent hybridization and high levels of introgression have caused different species in the same populations to share up to 50% of their genetic information.^[5] Having high rates of hybridization and introgression produces genetic data that often does not differentiate between two clearly morphologically distinct species, but instead differentiates populations.^[6] Numerous hypotheses have been proposed to explain how oak species are able to remain morphologically and ecologically distinct with such high levels of gene flow, but the problem is still largely a mystery to botanists.

The Fagaceae, or oak family, is a very slow evolving clade compared to other angiosperms,^[7][8] and the patterns of hybridization and introgression in Quercus pose a great challenge to the concept of a species since a species is often defined as a group of “actually or potentially interbreeding populations which are reproductively isolated from other such groups.”^[9] By this definition, many species of Quercus would be lumped together according to their geographic and ecological habitat, despite clear distinctions in morphology and, to a large extent, genetic data.

Uses[link]

Heart of oak beams of the frame of Saint-Girons church in Monein, France

Oak wood has a density of about 0.75 g/cm³, great strength and hardness, and is very resistant to insect and fungal attack because of its high tannin content. It also has very appealing grain markings, particularly when quartersawn. Wide, quarter-sawn boards of oak have been prized since the Middle Ages for use in interior paneling of prestigious buildings such as the debating chamber of the House of Commons in London, England, and in the construction of fine furniture. Oak wood, from Quercus robur and Quercus petraea, was used in Europe for the construction of ships, especially naval men of war, until the 19th century, and was the principal timber used in the construction of European timber-framed buildings. Today oak wood is still commonly used for furniture making and flooring, timber frame buildings, and for veneer production. Barrels in which wines, sherry, and spirits such as brandy, Scotch whisky and Bourbon whiskey are aged are made from European and American oak. The use of oak in wine can add many different dimensions to wine based on the type and style of the oak. Oak barrels, which may be charred before use, contribute to the colour, taste, and aroma of the contents, imparting a desirable oaky vanillin flavour to these drinks. The great dilemma for wine producers is to choose between French and American oakwoods. French oaks (Quercus robur, Q. petraea) give the wine greater refinement and are chosen for the best wines since they increase the price compared to those aged in American oak wood. American oak contributes greater texture and resistance to ageing, but produces more violent wine bouquets. Oak wood chips are used for smoking fish, meat, cheeses^[10] and other foods.

Sherry maturing in oak barrels

Japanese oak is used in the making of professional drums from manufacturer Yamaha Drums. The higher density of oak gives the drum a brighter and louder tone compared to traditional drum materials such as maple and birch.

A cross section of the trunk of a cork oak, Quercus suber

The bark of the Cork oak, is used to produce wine stoppers (corks). This species grows in the Mediterranean Sea region, with Portugal, Spain, Algeria and Morocco producing most of the world's supply. Of the North American oaks, the Northern red oak is the most prized of the red oak group for lumber, all of which is marketed as red oak regardless of the species of origin. It is not good for outdoor use due to its open capillaries. One can blow air through an end grain piece 10 inches long to make bubbles come out in a glass of water. These openings give fungus easy access when the finish deteriorates. The standard for the lumber of the white oak group – all of which is marketed as white oak – is the White Oak. White Oak is often used to make wine barrels. The wood of the deciduous Pedunculate Oak and Sessile Oak accounts for most of the European oak production, but evergreen species, such as Holm oak and Cork oak also produce valuable timber.

The bark of the White Oak is dried and used in medical preparations. Oak bark is also rich in tannin, and is used by tanners for tanning leather. Acorns are used for making flour or roasted for acorn coffee.

Oak galls were used for centuries as the main ingredient in manuscript ink, harvested at a specific time of year.^{[citation needed]} In Korea, oak bark is used to make shingles for traditional roof construction.

Biodiversity and ecology[link]

Oaks are keystone species in a wide range of habitats from Mediterranean semi-desert to subtropical rainforest. For example, oak trees are important components of hardwood forests, and certain species are particularly known to grow in associations with members of the Ericaceae in oak-heath forests.^[11][12] A number of kinds of truffles, including the two well known varieties, the black Périgord truffle^[13] and the white Piedmont truffle,^[14] have symbiotic relationships with oak trees.

Many species of oaks are under threat of extinction in the wild, largely due to land use changes, livestock grazing and unsustainable harvesting. For example, over the past 200 years, large areas of oak forest in the highlands of Mexico, Central America and the northern Andes have been cleared for coffee plantations and cattle ranching. There is a continuing threat to these forests from exploitation for timber, fuelwood and charcoal.^[15] In the USA, entire oak ecosystems have declined due to a combination of factors still imperfectly known, but thought to include fire suppression, increased consumption of acorns by growing mammal populations, herbivory of seedlings, and introduced pests.^[16] In a recent survey, 78 wild oak species have been identified as being in danger of extinction, from a global total of over 500 species.^[17] The proportion under threat may be much higher in reality, as there is insufficient information about over 300 species, making it near impossible to form any judgement of their status.

Diseases and pests[link]

Oak powdery mildew on pedunculate oak

Sudden Oak Death (Phytophthora ramorum) is a water mould that can kill oaks within just a few weeks. Oak Wilt, caused by the fungus Ceratocystis fagacearum (a fungus closely related to Dutch Elm Disease), is also a lethal disease of some oaks, particularly the red oaks (the white oaks can be infected but generally live longer). Other dangers include wood-boring beetles, as well as root rot in older trees which may not be apparent on the outside, often being discovered only when the trees come down in a strong gale. Oak apples are galls on oaks made by the gall wasp. The female kermes scale causes galls to grow on kermes oak. Oaks are used as food plants by the larvae of Lepidoptera (butterfly and moth) species such as the Gypsy Moth, Lymantria dispar, which can defoliate oak and other broadleaved tree species in North America.^[18]

A considerable number of galls are found on oak leaves, buds, flowers, roots, etc. Examples are Oak artichoke gall, Oak Marble gall, Oak apple gall, Knopper gall, and Spangle gall.

A number of species of fungus cause powdery mildew on oak species. In Europe the species Erysiphe alphitoides is the most common cause.^[19]

A new and as yet little understood disease of mature oaks, Acute oak decline, has been reported in parts of the UK since 2009.^[20]

Additionally, the Oak Processionary Moth (Thaumetopoea processionea) has become a serious threat in the UK since 2006. It defoliates the trees, and is hazardous to human health.

Toxicity[link]

The leaves and acorns of the oak tree are poisonous to cattle, horses, sheep, and goats in large amounts due to the toxin tannic acid, and cause kidney damage and gastroenteritis. Additionally, once livestock have a taste for the leaves and acorns, they may seek them out. Symptoms of poisoning include lack of appetite, depression, constipation, diarrhea (which may contain blood), blood in urine, and colic. The exception to livestock and oak toxicity is the domestic pig, which may be fed entirely on acorns in the right conditions, and has traditionally been pastured in oak woodlands (such as the Spanish dehesa and the English system of pannage) for hundreds of years. Acorns are also edible to humans in processed form, after leaching of the tannins. They are a staple part of the forage consumed by wildlife, including squirrels.

Cultural significance[link]

Oak branches on the coat of arms of Estonia

National symbol[link]

The oak is a common symbol of strength and endurance and has been chosen as the national tree of many countries. Already an ancient Germanic symbol (in the form of the Donar Oak, for instance), certainly since the early nineteenth century, it stands for the nation of Germany.^[21] In 2004 the Arbor Day Foundation^[22] held a vote for the official National Tree of the United States of America. In November 2004, Congress passed legislation designating the oak as America's National Tree.^[23]

Other countries have also designated the oak as their national tree including England, Estonia, France, Germany, Moldova, Latvia, Lithuania, Poland, the United States, Wales, Galicia, Bulgaria, and Serbia.^{[citation needed]}

Oaks as regional and state symbols[link]

The oak is the emblem of County Londonderry in Northern Ireland, as a vast amount of the county was covered in forests of the tree until relatively recently. The name of the county comes from the city of Derry, which originally in Irish was known as Doire meaning oak.

The Irish County Kildare derives its name from the town of Kildare which originally in Irish was Cill Dara meaning the Church of the Oak or Oak Church.

Iowa designated the oak as its official state tree in 1961; and the White Oak is the state tree of Connecticut, Illinois and Maryland. The Northern Red Oak is the provincial tree of Prince Edward Island, as well as the state tree of New Jersey. The Live Oak is the state tree of Georgia, USA.

The oak is a national symbol from the Basque Country, specially in the province of Biscay.

Military use[link]

Oak leaves are traditionally an important part of German Army regalia. They also symbolize rank in the United States Armed Forces. A gold oak leaf indicates an O-4 (Major or Lt. Commander), whereas a silver oak leaf indicates an O-5 (Lt. Colonel or Commander). Arrangements of oak leaves, acorns and sprigs indicate different branches of the United States Navy Staff corps officers. Oak leaves are embroidered onto the covers (hats) worn by field grade officers and flag officers in the United States armed services.

If a service member earns multiple awards of the same medal, then instead of wearing a ribbon or medal for each award, he or she wears one metal representation of an "oak leaf cluster" attached to the appropriate ribbon for each subsequent award.

Political use[link]

The oak tree is used as a symbol by a number of political parties. It is the symbol of the Conservative Party in the United Kingdom,^[24] and formerly of the Progressive Democrats in Ireland.^[25] In the cultural arena, the oakleaf is the symbol of the National Trust (UK) and The Royal Oak Foundation.^{[citation needed]}

Religious[link]

In Greek mythology, the oak is the tree sacred to Zeus, king of the gods. In Zeus's oracle in Dodona, Epirus, the sacred oak was the centerpiece of the precinct, and the priests would divine the pronouncements of the god by interpreting the rustling of the oak's leaves.^[26]

In Baltic mythology, the oak is the sacred tree of Latvian Pērkons, Lithuanian Perkūnas and Prussian Perkūns. Pērkons is the god of thunder and one of the most important deities in the Baltic pantheon.

In Celtic polytheism, the name of the oak tree was part of the Proto-Celtic word for 'druid': *derwo-weyd- > *druwid- ; however, Proto-Celtic *derwo- (and *dru-) can also be adjectives for 'strong' and 'firm', so Ranko Matasovic interprets that *druwid- may mean 'strong knowledge'. As in other Indo-European faiths, Taranus, being a Thunder God, was associated with the oak tree.

In Norse mythology, the oak was sacred to the thunder god, Thor. Some scholars speculate^{[weasel words]} that the reason for this is that the oak – the largest tree in northern Europe – was the one most often struck by lightning. Thor's Oak was a sacred tree of the Germanic Chatti tribe. According to legend, the Christianisation of the heathen tribes by Saint Boniface was marked by the oak's being replaced by the fir (whose triangular shape symbolizes the Trinity) as a "sacred" tree.^[27]

In the Bible, the oak tree at Shechem is the site where Jacob buries the foreign gods of his people (Gen. 35:4) . In addition, Joshua erects a stone under an oak tree as the first covenant of the Lord (Josh. 24.25-7). In Isaiah 61, the prophet refers to the Israelites as "Oaks of Righteousness".

In Slavic mythology, the oak was the most important tree of the god Perun.

Historical[link]

Several individual oak trees, such as the Royal Oak in Britain and the Charter Oak in the United States, are of great historical or cultural importance; for a list of important oaks, see Individual oak trees.

"The Proscribed Royalist, 1651", a famous painting by John Everett Millais, depicted a Royalist fleeing from Cromwell's forces and hidden in an oak. Millais painted the picture in Hayes, Kent, from a local oak tree that became known as the Millais Oak.^[28][29]

Approximately 50 km west of Toronto, Canada is the town of Oakville, ON, famous for its history as a shipbuilding port on Lake Ontario.

The city of Raleigh, N.C., is known as "The City of Oaks."

The Jurupa Oak tree — a clonal colony of Quercus palmeria or Palmer’s Oak found in Riverside County, California — is believed to be the world's oldest organism at 13,000 years.^[30]

Large groups of very old oak trees are rare. One of the oldest groups of oak trees, found in Poland, is about 480 years old, which was assessed by dendrochronological methods^[31].

Historical note on Linnaean species[link]

Linnaeus described only five species of oak from eastern North America, based on general leaf form. These were White oak, Quercus alba; Chestnut oak, Q. montana; Red oak, Q. rubra; Willow oak Q. phellos; and Water oak, Q. nigra. Because he was dealing with confusing leaf forms, the Q. prinus and Q. rubra specimens actually included mixed foliage of more than one species. For that reason, some taxonomists in the past proposed different names for these two species (Q. montana and Q. borealis, respectively), but the original Linnaean names have now been lectotypified by removing some of the specimens in Linnaeus' herbarium.

See also[link]

• List of plants poisonous to equines
• Thousand Oaks, California
• Foloi oak forest

References[link]

Bibliography[link]

• Byfield, Liz (1990) An oak tree, Collins book bus, London : Collins Educational, ISBN 0-00-313526-8
• Philips, Roger. Trees of North America and Europe, Random House, Inc., New York ISBN 0-394-50259-0, 1979.
• Logan, William B. (2005) Oak : the frame of civilization, New York ; London : W.W. Norton, ISBN 0-393-04773-3
• Paterson, R.T. (1993) Use of trees by livestock, 5: Quercus, Chatham : Natural Resources Institute, ISBN 0-85954-365-X
• Royston, Angela (2000) Life cycle of an oak tree, Heinemann first library, Oxford : Heinemann Library, ISBN 0-431-08391-6
• Savage, Stephen (1994) Oak tree, Observing nature series, Hove : Wayland, ISBN 0-7502-1196-2
• Tansley, Arthur G., Sir (1952) Oaks and oak woods, Field study books, London : Methuen.
• Żukow-Karczewski, Marek. Dąb – król polskich drzew (Oak – the king of the Polish trees), "AURA" (A Monthly for the protection and shaping of human environment), 9/88.

External links[link]

Wikimedia Commons has media related to: Quercus

Wikispecies has information related to: Quercus

• Flora of China – Cyclobalanopsis
• Flora Europaea: Quercus
• Oaks from Bialowieza Forest
• Common Oaks of Florida
• Oaks of the world
• The Global Trees Campaign The Red List of Oaks and Global Survey of Threatened Quercus
• Janka Hardness Scale for Oak – The Janka Hardness Scale for all Exotic and Domestic species

Trees on a mountain in northern Utah during early autumn

Trunk base of a Coast Redwood tree in Jedediah Smith Redwoods State Park: Simpson Reed Discovery Trail, near Crescent City, California

A tree is a perennial woody plant. It most often has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance.^[1] A minimum height specification at maturity is cited by some authors, varying from 3 m^[2] to 6 m;^[3] some authors set a minimum of 10 cm trunk diameter (30 cm girth).^[4] Woody plants that do not meet these definitions by having multiple stems and/or small size are usually called shrubs, although many trees such as Mallee do not meet such definitions. Compared with most other plants, trees are long-lived, some reaching several thousand years old and growing to up to 115 m (379 ft) high.^[5]

Trees are an important component of the natural landscape because of their prevention of erosion and the provision of a weather-sheltered ecosystem in and under their foliage. They also play an important role in producing oxygen and reducing carbon dioxide in the atmosphere, as well as moderating ground temperatures. They are also elements in landscaping and agriculture, both for their aesthetic appeal and their orchard crops (such as apples). Wood from trees is a building material, as well as a primary energy source in many developing countries. Trees also play a role in many of the world's mythologies (see trees in mythology).^[6]

Classification[link]

A tree is a plant form that occurs in many different orders and families of plants. Most species of trees today are flowering plants (angiosperms) and conifers. Trees show a variety of growth forms, leaf type and shape, bark characteristics and reproductive organs. For the listing of examples of well-known trees and how they are classified, see List of tree genera.

The tree form has evolved separately in unrelated classes of plants, in response to similar environmental challenges, making it a classic example of parallel evolution. With an estimate of 100,000 tree species, the number of tree species worldwide might total 25 percent of all living plant species.^[7] The majority of tree species grow in tropical regions of the world and many of these areas have not been surveyed yet by botanists, making species diversity and ranges poorly understood.^[8] The earliest tree-like organisms were tree ferns, horsetails and lycophytes, which grew in forests in the Carboniferous period, however these plants were not trees^{[citation needed]}, since they lacked woody tissue. Trees evolved in the Triassic period, with conifers, ginkgos, cycads and other gymnosperms appeared producing woody tissue, and were subsequently followed by tree-form flowering plants in the Cretaceous period.

A small group of trees growing together is called a grove or copse, and a landscape covered by a dense growth of trees is called a forest. Several biotopes are defined largely by the trees that inhabit them; examples are rainforest and taiga (see ecozones). A landscape of trees scattered or spaced across grassland (usually grazed or burned over periodically) is called a savanna. A forest of great age is called old growth forest or ancient woodland (in the UK). A young tree is called a sapling.

Morphology[link]

Tree roots anchor the structure and provide water and nutrients. The ground has eroded away around the roots of this young red pine tree.

Many trees show strong apical dominance.

The parts of a tree are the roots, trunk(s), branches, twigs and leaves. Tree stems consist mainly of support and transport tissues (xylem and phloem). Wood consists of xylem cells, and bark is made of phloem and other tissues external to the vascular cambium. Trees may be grouped into exogenous and endogenous trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of trees (all conifers, and almost all broadleaf trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the monocotyledons (e.g., aloes and dragon trees), grow by addition of new material as discrete bundles within the existing trunk tissue.

Trees can be identified to genus or species by a combination of the tree's shape, and the characteristics of its bark, leaves, flowers, and fruit. The leaves may be either deciduous or evergreen.^[2][3]

As an exogenous tree grows, it creates growth rings as new wood is laid down concentrically over the old wood. In species growing in areas with seasonal climate changes, wood growth produced at different times of the year may be visible as alternating light and dark, or soft and hard, rings of wood.^[3] In temperate climates, and tropical climates with a single wet-dry season alternation, the growth rings are annual, each pair of light and dark rings being one year of growth; these are known as annual rings. In areas with two wet and dry seasons each year, there may be two pairs of light and dark rings each year; and in some (mainly semi-desert regions with irregular rainfall), there may be a new growth ring with each rainfall.^[9] In tropical rainforest regions, with constant year-round climate, growth is continuous and the growth rings are not visible nor is there a change in the wood texture. In species with annual rings, these rings can be counted to determine the age of the tree, and used to date cores or even wood taken from trees in the past, a practice known as the science of dendrochronology. Very few tropical trees can be accurately dated in this manner. Age determination in this manner is also impossible in endogenous trees.

The roots of a tree are generally embedded in earth, providing anchorage for the above-ground biomass and absorbing water and nutrients from the soil. However, while ground nutrients are essential to a tree's growth the majority of its biomass – over 90 percent – comes from carbon dioxide absorbed from the atmosphere (see photosynthesis).^[10] Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for sunlight. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight.

Not all trees have all the plant organs or parts mentioned above. For example, the saguaro cactus of North America has no functional leaves. A plant form that is similar to a tree, but generally having smaller, multiple trunks and/or branches that arise near the ground, is called a shrub. However, no precise differentiation between shrubs and trees is possible. Given their small size, bonsai plants would not technically be "trees", but one should not confuse reference to the form of a species with the size or shape of individual specimens. A spruce seedling does not fit the definition of a tree, but all spruces are trees.

Record breaking trees[link]

The world's champion trees can be rated on height, trunk diameter or girth, total size, and age.

Tallest trees[link]

The coniferous Coast Redwood is the tallest tree species on earth.

The heights of the tallest trees in the world have been the subject of considerable dispute and much exaggeration. Modern verified measurements with laser rangefinders, or with tape drop measurements made by tree climbers (such as those carried out by canopy researchers or members of groups like the Native Tree Society), have shown that some older measuring methods and measurements are often unreliable, sometimes producing exaggerations of 5% to 15% or more above the real height. Historical claims of trees growing to 130 m (430 ft), and even 150 m (490 ft), are now largely disregarded as unreliable, and attributed to human error. Historical records of fallen trees measured prostrate on the ground are considered to be somewhat more reliable. The following are now accepted as the top nine tallest reliably measured species (taken only currently standing specimens):

1. Coast Redwood (Sequoia sempervirens): 115.66 m (379.46 ft), Hyperion, Redwood National Park, California, United States^[11]
2. Coast Douglas-fir (Pseudotsuga menziesii): 99.76 m (327.3 ft), Brummit Creek, Coos County, Oregon, United States^[12]
3. Australian Mountain Ash (Eucalyptus regnans): 99.6 m (327 ft), south of Hobart, Tasmania, Australia^[13]
4. Sitka Spruce (Picea sitchensis): 96.7 m (317 ft), Prairie Creek Redwoods State Park, California, United States^[14]
5. Giant Sequoia (Sequoiadendron giganteum): 95.8 m (314 ft), Sequoia National Forest, California, United States^[15]
6. Tasmanian Blue Gum (Eucalyptus globulus): 90.7 m (298 ft), Tasmania, Australia^[16]
7. Manna Gum (Eucalyptus viminalis): 89 m (292 ft), Evercreech Forest Reserve, Tasmania, Australia^[16]
8. Shorea faguetiana: 88.3 m (290 ft) Tawau Hills National Park, in Sabah on the island of Borneo^[17]
9. Alpine Ash (Eucalyptus delegatensis): 87.9 m (288 ft), Tasmania, Australia^[16]

A view of a tree from below; this may exaggerate apparent height

Stoutest trees[link]

The girth of a tree is usually much easier to measure than the height, as it is a simple matter of stretching a tape round the trunk, and pulling it taut to find the circumference. Despite this, UK tree author Alan Mitchell made the following comment about measurements of yew trees:

The aberrations of past measurements of yews are beyond belief. For example, the tree at Tisbury has a well-defined, clean, if irregular bole at least 1.5 m long. It has been found to have a girth that dilated and shrunk in the following way: 11.28 m (1834 Loudon), 9.3 m (1892 Lowe), 10.67 m (1903 Elwes and Henry), 9.0 m (1924 E. Swanton), 9.45 m (1959 Mitchell) ... Earlier measurements have therefore been omitted.

As a general standard, tree girth is taken at "breast height". This is cited as dbh (diameter at breast height) in tree and forestry literature.^[3][18] Breast height is defined differently in different situations, with most forestry measurements taking girth at 1.3 m above ground,^[18] while those who measure ornamental trees usually measure at 1.5 m above ground;^[3] in most cases this makes little difference to the measured girth. On sloping ground, the "above ground" reference point is usually taken as the highest point on the ground touching the trunk^[3][18], but in North America a point, that is the average of the highest point and the lowest point the tree trunk appears to contact the soil, is usually used.^[19] Some of the inflated old measurements may have been taken at ground level. Some past exaggerated measurements also result from measuring the complete next-to-bark measurement, pushing the tape in and out over every crevice and buttress.^[20]

Modern trends are to cite the tree's diameter rather than the circumference. Diameter of the tree is calculated by finding the medium diameter of the trunk, in most cases obtained by dividing the measured circumference by π; this assumes the trunk is mostly circular in cross-section (an oval or irregular cross-section would result in a mean diameter slightly greater than the assumed circle). Accurately measuring circumference or diameter is difficult in species with the large buttresses that are especially characteristic in many species of rainforest trees. Simple measurement of circumference of such trees can be misleading when the circumference includes much empty space between buttresses.

One further problem with measuring baobabs Adansonia is that these trees store large amounts of water in the very soft wood in their trunks. This leads to marked variation in their girth over the year (though not more than about 2.5%^[21]), swelling to a maximum at the end of the rainy season, minimum at the end of the dry season.

The stoutest living single-trunk species in diameter are:

1. Montezuma Cypress Taxodium mucronatum: 11.62 m (38.1 ft), Árbol del Tule, Santa Maria del Tule, Oaxaca, Mexico.^[22] Note though that this diameter includes buttressing; the actual idealised diameter of the area of its wood is 9.38 m (30.8 ft).^[22]
2. Giant Sequoia Sequoiadendron giganteum: 8.85 m (29.0 ft), General Grant tree, General Grant Grove, California, United States^[23]
3. Coast Redwood Sequoia sempervirens: 7.9 m (26 ft), Lost Monarch Jedediah Smith Redwoods State Park, California, United States.
4. Australian Oak Eucalyptus obliqua: 6.72 m (22.0 ft)
5. Australian Mountain Ash Eucalyptus regnans: 6.52 m (21.4 ft), Big Foot
6. Western Redcedar Thuja plicata: 5.99 m (19.7 ft), Kalaloch Cedar, Olympic National Park
7. Sitka Spruce Picea sitchensis: 5.39 m (17.7 ft), Quinalt Lake Spruce, Olympic National Park
8. Kauri Agathis australis (Te Matua Ngahere): 5.33 m (17.5 ft).^[24]
9. Alerce Fitzroya cupressoides: 5.0 m (16.4 ft)

An additional problem lies in instances where multiple trunks (whether from an individual tree or multiple trees) grow together. The Sacred Fig is a notable example of this, forming additional "trunks" by growing adventitious roots down from the branches, which then thicken up when the root reaches the ground to form new trunks; a single Sacred Fig tree can have hundreds of such trunks.^[1] The multi-stemmed Hundred Horse Chestnut was known to have a circumference of 57.9 m (190 ft) when it was measured in 1780.

Largest trees[link]

General Sherman is the largest tree on Earth

The largest trees in total volume are both tall and large in diameter and, in particular, hold a large diameter high up the trunk. Measurement is very complex, particularly if branch volume is to be included as well as the trunk volume, so measurements have only been made for a small number of trees, and generally only for the trunk. No attempt has ever been made to include root volume. Measuring standards vary.

The top ten species measured so far are*:

1. Giant Sequoia Sequoiadendron giganteum: 1,487 m³ (52,508 cu ft), General Sherman^[25]
2. Coast Redwood Sequoia sempervirens: 1,203 m³ (42,500 cu ft), Lost Monarch^[26]
3. Montezuma Cypress Taxodium mucronatum: 750 m³ (25,000 cu ft), Árbol del Tule^[27]
4. Kauri Agathis australis (Tāne Mahuta): 516 m³ ^[28]
5. Western Redcedar Thuja plicata: 500 m³ (17,650 cu ft ), Quinault Lake Redcedar^[25]
6. Tasmanian Blue Gum Eucalyptus globulus: 368 m³ (13,000 cu ft), Rullah Longatyle (Strong Girl, also Grieving Giant) ^[16]
7. Australian Mountain Ash Eucalyptus regnans: 360 m³ (12,714 cu ft), Arve Big Tree^[16]
8. Coast Douglas-fir Pseudotsuga menziesii 349 m³ (12,320 cu ft) Red Creek Tree
9. Sitka Spruce Picea sitchensis 337 m³ (11,920 cu ft) Queets Spruce^[29]
10. Australian Oak Eucalyptus obliqua: 337 m³ (11,920 cu ft) Gothmog^[16]
11. Alpine Ash Eucalyptus delegatensis: 286 m³ (10,100 cu ft), located in Styx River Valley^[16]

(*)This list does not take into account now dead specimens.

Oldest trees[link]

The oldest trees are determined by growth rings, which can be seen if the tree is cut down, or in cores taken from the bark to the center of the tree. Accurate determination is only possible for trees that produce growth rings, generally those in seasonal climates. Trees in uniform non-seasonal tropical climates grow continuously and do not have distinct growth rings. It is also only possible for trees that are solid to the center. Many very old trees become hollow as the dead heartwood decays. For some of these species, age estimates have been made on the basis of extrapolating current growth rates, but the results are usually largely speculation. White (1998)^[30] proposes a method of estimating the age of large and veteran trees in the United Kingdom through the correlation between a tree's stem diameter, growth character and age.

The verified oldest measured ages are:

1. Great Basin Bristlecone Pine (Methuselah) Pinus longaeva: 4,844 years^[31]
2. Alerce Fitzroya cupressoides: 3,622 years^[31]
3. Giant Sequoia Sequoiadendron giganteum: 3,266 years^[31]
4. Sugi Cryptomeria japonica: 3,000 years^[32]
5. Huon-pine Lagarostrobos franklinii: 2,500 years^[31]

Other species suspected of reaching exceptional age include European Yew Taxus baccata (probably over 2,000 years^[33][34]) and Western Redcedar Thuja plicata. The oldest known European Yew is the Llangernyw Yew in the Churchyard of Llangernyw village in North Wales, which is estimated to be between 4,000 and 5,000 years old.

Damage[link]

El Grande, about 85 m (279 ft) high, the most massive (though not the tallest) Eucalyptus regnans was accidentally killed by loggers burning-off the remains of legally loggable trees (less than 85 m) that had been felled all around it.

Callus growth on beech branch following fire (heat) damage.

The two sources of tree damage are either biotic (from living sources) or abiotic (from non-living sources). Biotic sources include insects that bore into the tree, deer that rub bark off, and fungi.^[35]

Abiotic sources include lightning, vehicles impacts, and construction activities. Construction activities can involve a number of damage sources, including grade changes that prevent aeration to roots, spills involving toxic chemicals such as cement or petroleum products, or severing of branches or roots.

Both damage sources can result in trees becoming dangerous, and the term "hazard trees" is commonly used by arborists, and industry groups such as power line operators. Hazard trees are trees that, due to disease or other factors, are more susceptible to falling in windstorms, or having parts of the tree fall.

Evaluating the danger a tree presents is based on a process called the Quantified Tree Risk Assessment.^[36]

Assessment as to labeling a tree a hazard tree can be based on a field examination. Assessment as a result of construction activities that will damage a tree is based on three factors: severity, extent and duration. Severity relates usually to the degree of intrusion into the TPZ and resultant root loss. Extent is frequently a percentage of a factor such as canopy, roots or bark, and duration is normally based on time. Root severing is considered permanent in time.

Trees are similar to people. Both can withstand massive amounts of some types of damage and survive, but even small amounts of certain types of trauma can result in death. Arborists are very aware that established trees will not tolerate any appreciable disturbance of the root system.^[37] However, lay people and construction professionals seldom recognise how easily a tree can be killed.

One reason for confusion about tree damage from construction involves the dormancy of trees during winter. Another factor is that trees may not show symptoms of damage until two years or longer after damage has occurred. For that reason, persons uneducated in arboricultural science may not correlate the actual cause and resultant effect.

Various organisations, such as the International Society of Arboriculture, the British Standards Institute and the Tree Industry Association (formerly the National Arborist Association), have long recognised the importance of construction activities that impact tree health. The impacts are important because they can result in monetary losses due to tree damage and resultant remediation or replacement costs, as well as violation of government ordinances or community or subdivision restrictions.

As a result, protocols for tree management prior to, during and after construction activities are well established, tested and refined. These basic steps are involved:

• Review of the construction plans
• Development of the related tree inventory
• Application of standard construction tree management protocols
• Assessment of potential for expected tree damages
• Development of a tree protection plan (providing for pre-, concurrent, and post construction damage prevention and remediation steps)
• Development of a tree protection plan
• Development of a remediation plan
• Implementation of tree protection zones (TPZ)
• Assessment of construction tree damage, post-construction
• Implementation of the remediation plan

The shield of Currier House (Harvard College).

Trees in culture[link]

The tree has always been a cultural symbol. Common icons are the World tree, for instance Yggdrasil,^[38] and the tree of life. The tree is often used to represent nature or the environment itself.

The tree is also a symbol and mascot for Stanford University and Currier House (Harvard College).

Tree value approximation (USA)[link]

Studies have shown that trees contribute as much as 27% of the appraised land value in certain markets and cite the following^[39] which can be extrapolated with care.

These most likely use diameter measured at breast height, 4.5 feet (140 cm) above ground, not the larger base diameter. A general model for any year and diameter is Value = 17.27939*(diameter^2)*1.022^(year-1985) assuming 2.2% inflation per year.^[41] The right side of this equation is written to paste into Excel or Google to perform the calculation. Extrapolations from any model can vary widely, so value estimates for diameters larger than 30 inches (760 mm) may have to be capped so trees do not exceed 27% of total appraised land value.

See also[link]

References[link]

Notes[link]

Bibliography[link]

• Pakenham, T. (2002). Remarkable Trees of the World. ISBN 0-297-84300-1
• Pakenham, T. (1996). Meetings with Remarkable Trees. ISBN 0-297-83255-7
• Tudge, C. (2005). The Secret Life of Trees. How They Live and Why They Matter. Allen Lane. London. ISBN 0-7139-9698-6

External links[link]

Trees portal

Wikimedia Commons has media related to: Trees

Look up tree in Wiktionary, the free dictionary.

• Gymnosperm database
• Silvics of North America
• University of Florida's Landscape Plants website
• Global Trees Campaign (campaigning to save the world's most threatened trees)
• International Society of Arboriculture
• Eastern Native Tree Society
• Western Native Tree Society
• Trees The Arbor Day Foundation
• Tree Encyclopedia Extensive collection of diagnostic photos, Morton Arboretum Specimens
• Wondermondo - Trees Largest and most unusual trees of the world
• Venerable Trees Venerable trees of the planet

lez:Ттарvep:Pu

Morris E. Day (born December 13, 1957) is an American musician, composer and actor. He is best known as the lead singer of The Time.

Musical career[link]

1970s and 1980s[link]

In high school, Day was in a band with Prince and André Cymone and the trio formed an early band managed by Day's mother called "Grand Central," later renamed "Champagne." Later, Prince embarked on a solo career but retained Cymone for his backing band. The two began to plan a side-group that would focus more on R&B, while Prince would continue to explore various musical styles. The Time was composed of 4 members from an earlier funk group called "Flyte Tyme," but the lead singer had not been chosen. Charles Cobb was considered but he turned it down. Sue Ann Carwell was auditioned; and Alexander O'Neal nearly became The Time's lead singer, but dropped out due to payment negotiations. Day, who was now in a band called "Enterprise", allowed Prince to have a song called "Partyup" for his Dirty Mind album, and Prince would soon return the favor by giving Day the job of lead singer. Day would suggest guitarist Jesse Johnson, who completed the band's ensemble.

The Time's most prolific and visible period came in 1984, when Day played the antagonist to Prince in his feature films Purple Rain and Graffiti Bridge, which helped establish Day's playboy stage presence. Typically escorted by his valet, "Jerome" (Jerome Benton), Day won fans with his exaggerated vanity ("Jerome bring me my mirror!") and strutting bravado ("Ain't nobody bad like me!"), acting as a comic foil to Prince's romantic, sensitive lead. This persona was further exploited for comic effect on The Time's records, on songs such as "Chili Sauce" and "If the Kid Can't Make You Come" from the album Ice Cream Castle.

That album, the group's most popular, is best remembered for the infectious singles "Jungle Love" and the Rufus Thomas influenced, "The Bird." With their palpable pop energy and catchy choruses, both songs were hits on both urban and pop radio.

In 1984, Day appeared on a duet with singer Vanity on "Mechanical Emotion" from her debut album Wild Animal. With the breakup of The Time that same year, Day began his solo career. The low sales of his solo albums such as 1987's Daydreaming (which spawned the single "Fishnet") and his most commercially viable solo album, Guaranteed were a blow to his career.

In 1986 Morris Day married Judith Day. They were married for 22 years—until 2008. They had three children together.

1990s[link]

It wasn't until 1990 that The Time scored a #1 R&B hit with "Jerk Out," a Dance-funk cut from their reunited fourth album, Pandemonium. This album also featured the original members of the band. The same year, Day formed his own girl band (not unlike Prince's Vanity 6/Apollonia 6) called The Day Zs. The group's first and only album release was produced by Day and he sang on one of the tracks called "Green Acres."

From that high point, Day's success began to wane. The general decline of Prince's popularity soon after did not help and Day's public visibility, and his creative output waned considerably.

2000 to present[link]

Day came out of his self-imposed retirement because of his fans' support. Day has remained a popular concert draw since the late 1990s, fronting a revamped lineup of The Time, including originals Jellybean Johnson on drums and Monte Moir on keyboards. The band was invited to perform on Prince's direct to video concert film, "Rave Un2 The Year 2000", in December 1999.

Day has also appeared regularly in local television commercials for a Toyota dealership in the Atlanta area.

As of 2007, Day is band leader on the TV One program Baisden After Dark.

He reunited with the original members of The Time after 18 years for a performance with Rihanna at the 50th Grammy Awards show.

Morris Day and The Time performed at the 2008 HR Florida State Conference.

Acting career[link]

Day continued to act in films from time to time in small parts (including a brief but memorable turn in Richard Pryor's Moving, and the Andrew Dice Clay (1990 film) The Adventures of Ford Fairlane). Day's presence on the screen decreased until, in 2001, he returned to film in Kevin Smith's Jay and Silent Bob Strike Back, performing "Jungle Love" with The Time and dancing with the movie's stars in the film's coda, and being introduced emphatically by Jason Mewes' character as "Morris Day and The motherfuckin' Time!".

Day also appeared on the small screen in 1990 when he portrayed the character Lamarr on ABC's short-lived sitcom New Attitude. He guest-starred on the sitcom Eve as a pimp who wanted Eve's fashion boutique to design a flamboyant suit to match his witty personality, and appeared as himself in an episode on the series Moesha, attempting to file a lawsuit against Moesha's ex-boyfriend Q, who used a sample from "The Oak Tree" without permission. He also appeared on 227 in the 80's.

He appeared opposite James Avery and Matthew Stewart in a pilot called Heart & Soul.

Appearances in popular culture[link]

In the 1980s and 1990s, WWF wrestler "Birdman" Koko B. Ware used "The Bird" as his entrance theme.

He appeared with The Time at the end of the movie "Jay and Silent Bob Strike Back" and was referred to as the main characters' favorite band.

In 1994, Day was featured on and provided the chorus and accompanying vocals for rapper K-Dee's song "Gigolos Get Lonely Too" from the Ass, Gas, or Cash (No One Rides for Free) album. This song was essentially a direct sampling of a similarly named "Gigolos Get Lonely Too", recorded by The Time in the 80's.

A song called "Morris Day" appears on the album Felt, Vol. 2: A Tribute to Lisa Bonet by the hip-hop group Felt.

Discography[link]

Albums[link]

The Time[link]

• The Time (Warner Bros., 1981)
• What Time Is It? (Warner Bros., 1982)
• Ice Cream Castle (Warner Bros., 1984)
• Pandemonium (Paisley Park Records, 1990) #18 US
• Condensate (as The Original 7ven)( Saguaro Road Records 2011)

Solo[link]

• Color of Success (Warner Bros., 1985)
• Daydreaming (Warner Bros., 1987)
• Guaranteed (Reprise, 1992)
• It's About Time (Hollywood, 2004)

Singles[link]

Solo[link]

The Time[link]

Filmography[link]

With Prince[link]

• Graffiti Bridge
• Purple Rain

Other appearances[link]

• Jay and Silent Bob Strike Back
• Moesha
• Moving
• The Adventures of Ford Fairlane
• Eve

References[link]

External links[link]

• Official website
• Morris Day at the Internet Movie Database