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Creekline Miniritchie

Creekline miniritchie

Acacia cyperophylla, commonly known as creekline miniritchie or red mulga, is a tree in the family Fabaceae. Endemic to Western Australia, it on the banks of rivers and creeks on the semi-arid plains east of Carnarvon. Creekline miniritchie grows to a height of about seven metres. It usually has just one or two main trunks. Like most Acacia species, it has phyllodes rather than true leaves. These are rigid, round in cross-section with a diameter of about two millimetres, between ten and fifteen centimetres long, and curved. The flowers are yellow, and held in cylindrical clusters about two centimetres long. The pods are broad and flat, about eight centimetres long and seven millimetres wide. Creekline miniritchie is most readily identified by its distinctive "minni ritchi" bark, which constantly peels off in small curling flakes, making the tree look like it has a coat of curly hair. On creekline miniritchie, this is an orange-brown colour. There are two varieties, A. cyperophylla var. cyperophylla and A. cyperophylla var. omearana. The latter variety is known from only a few populations near Port Hedland, all of which are under threat. It has been classified "Priority 1" under the Western Australian Wildlife Conservation Act, and is under consideration for declaration as "rare flora".

References


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- Category:Flora of Western Australia Category:Acacia

Tree

, the tallest tree species on earth]] A tree can be defined as a large, perennial, woody plant. Though there is no set definition regarding minimum size, the term generally applies to plants at least 6 m (20 ft) high at maturity and, more importantly, having secondary branches supported on a single main stem or trunk (see shrub for comparison). Compared with most other plant forms, trees are long-lived. A few species of trees grow to 100 m tall, and some can live for several thousand years. Trees are important components of the natural landscape and significant elements in landscaping, and in agriculture supplying orchard crops (such as apples). Trees also play an important role in many of the world's mythologies (see Tree (mythology)).

Classifications

Tree (mythology)]] A tree is a plant form and trees occur in many different orders and families of plants. Trees thus show a wide variety of growth form, leaf type and shape, bark characteristics, reproductive structures, etc. The earliest trees were tree ferns and horsetails, which grew in vast forests in the Carboniferous Period; tree ferns still survive, but the only surviving horsetails are not of tree form. Later, in the Triassic Period, conifers, ginkgos, cycads and other gymnosperms appeared, and subsequently flowering plants in the Cretaceous Period. Most species of trees today are flowering plants and conifers. The listing below gives examples of many well-known trees and how they are typically classified. 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.

Morphology

The basic 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 broadly grouped into exogenous and endogenous trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of modern trees (all conifers, and all broadleaf trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the monocotyledons (e.g. palms), grow by addition of new material inwards. As an exogenous tree grows, it creates growth rings. In temperate climates, these are commonly visible due to changes in the rate of growth with temperature variation over an annual cycle. 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; this practice is known as the science of dendrochronology. In some tropical regions with constant year-round climate, growth is continuous and distinct rings are not formed, so age determination is impossible. Age determination is also impossible in endogenous trees. dendrochronology, Chile]] 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. 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, most palm trees are not branched, the saguaro cactus of North America has no functional leaves, tree ferns do not produce bark, etc. Based on their general shape and size, all of these are nonetheless generally regarded as trees. Indeed, sometimes size is the more important consideration. 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 sharp 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. Bamboos by contrast, do show most of the characteristics of trees, yet are rarely called trees.

Champion trees

The world's champion trees can be considered on several factors; height, trunk diameter or girth, total size, and age. It is significant that in each case, the top position is always held by a conifer, though a different species in each case; in most measures, the second to fourth places are also held by conifers. ;Tallest trees The heights of the tallest trees in the world have been the subject of considerable dispute and much (often wild) exaggeration. Modern verified measurement with laser rangefinders combined with tape drop measurements made by tree climbers, carried out by the [http://www.uark.edu/misc/ents/home.htm U.S. Eastern Native Tree Society] has shown that most older measuring methods and measurements are unreliable, often producing exaggerations of 5% to 15% above the real height. Historical claims of trees of 114 m, 117 m, 130 m, and even 150 m, are now largely disregarded as unreliable, fantasy or outright fraud. The following are now accepted as the top five tallest reliably measured species: # Coast Redwood Sequoia sempervirens: 112.83 m, Humboldt Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database]) # Coast Douglas-fir Pseudotsuga menziesii: 100.3 m, Brummit Creek, Coos County, Oregon ([http://www.conifers.org/pi/ps/menziesii2.htm Gymnosperm Database]) # Sitka Spruce Picea sitchensis: 96.7 m, Prairie Creek Redwoods State Park, California ([http://www.conifers.org/pi/pic/sitchensis.htm Gymnosperm Database]) # Giant Sequoia Sequoiadendron giganteum: 93.6 m, Redwood Mountain Grove, California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database]) # Australian Mountain-ash Eucalyptus regnans: 92.0 m, Styx Valley, Tasmania ([http://www.forestrytas.com.au/forestrytas/tasfor/tasforests_12/tasfor_12_09.pdf Forestry Tasmania] [pdf file]) ;Stoutest trees The girth (circumference) of a tree is – or at least should be – 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, U.K. tree author Alan Mitchell made the following comment about measurements of yew trees in the British Isles: :"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 which has 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 defined differently in different situations, with most foresters measuring girth at 1.3 m above ground, while ornamental tree measurers usually measure at 1.5 m above ground; 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, but some use the average between the highest and lowest points of ground. 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. Modern trends are to cite the tree's diameter rather than the circumference; this is obtained by dividing the measured circumference by π; it assumes the trunk is circular in cross-section (an oval or irregular cross-section would result in a mean diameter slightly greater than the assumed circle). This is cited as dbh (diameter at breast height) in tree literature. A 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, swelling to a maximum at the end of the rainy season, minimum at the end of the dry season. Although baobabs have some of the highest girth measurements of any trees, no accurate measurements are currently available, but probably do not exceed 10-11 m diameter. The stoutest species in diameter, excluding baobabs, are: # Montezuma Cypress Taxodium mucronatum: 11.42 m, Árbol del Tule, Santa Maria del Tule, Oaxaca, Mexico (A. F. Mitchell, International Dendrology Society Year Book 1983: 93, 1984). # Giant Sequoia Sequoiadendron giganteum: 8.85 m, General Grant tree, Grant Grove, California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database]) # Coast Redwood Sequoia sempervirens: 7.44 m, Prairie Creek Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database]) ;Largest trees The largest trees in total volume are those which are both tall and of large diameter, and in particular, which 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. The top four species measured so far are ([http://www.conifers.org/topics/biggest.htm Gymnosperm Database]): # Giant Sequoia Sequoiadendron giganteum: 1489 m³, General Sherman tree # Coast Redwood Sequoia sempervirens: 1045 m³, Del Norte Titan tree # Western Redcedar Thuja plicata: 500 m³, Quinault Lake Redcedar # Kauri Agathis australis: 400 m³, Tane Mahuta tree (total volume, including branches, 516.7 m³)
However, the Alerce Fitzroya cupressoides, as yet un-measured, may well slot in at third or fourth place, and Montezuma Cypress Taxodium mucronatum is also likely to be high in the list. The largest angiosperm tree is a Australian Mountain-ash, the 'El Grande' tree of about 380 m³ in Tasmania. ;Oldest trees The oldest trees are determined by growth ring counts in cores taken from the edge to the centre of the tree or from entire cross-sections. Accurate determination is only possible for trees which produce growth rings, generally those which occur 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 which are solid to the centre of the tree; many very old trees become hollow as the dead heartwood decays away. For some of these species, age estimates have been made on the basis of extrapolating current growth rates, but the results are usually little better than guesswork or wild speculation. The verified oldest measured ages are ([http://www.conifers.org/topics/oldest.htm Gymnosperm Database]): # Great Basin Bristlecone Pine Pinus longaeva: 4844 years # Alerce Fitzroya cupressoides: 3622 years # Giant Sequoia Sequoia sempervirens: 3266 years # Huon-pine Lagarostrobos franklinii: 2500 years # Rocky Mountains Bristlecone Pine Pinus aristata: 2435 years Other species suspected of reaching exceptional age include European Yew Taxus baccata (probably over 3000 years) and Western Redcedar Thuja plicata. The oldest verified age for an angiosperm tree is 2293 years for the Sri Maha Bodhi Sacred Fig (Ficus religiosa) planted in 288 BC at Anuradhapura, Sri Lanka; this is also the oldest human-planted tree with a known planting date.

Major tree genera

Flowering plants (Magnoliophyta; angiosperms)

Dicotyledons (Magnoliopsida; broadleaf or hardwood trees)


- Anacardiaceae (Cashew family)
  - Cashew, Anacardium occidentale
  - Mango, Mangifera indica
  - Pistachio, Pistacia vera
  - Sumac, Rhus species
  - Lacquer tree, Toxicodendron verniciflua
- Annonaceae (Custard apple family)
  - Cherimoya Annona cherimola
  - Custard apple Annona reticulata
  - Pawpaw Asimina triloba
  - Soursop Annona muricata
- Apocynaceae (Dogbane family)
  - Pachypodium Pachypodium species
- Aquifoliaceae (Holly family)
  - Holly, Ilex species
- Araliaceae (Ivy family)
  - Kalopanax, Kalopanax pictus Kalopanax tree (background) in fall]]
- Betulaceae (Birch family)
  - Alder, Alnus species
  - Birch, Betula species
  - Hornbeam, Carpinus species
  - Hazel, Corylus species
- Bignoniaceae (family)
  - Catalpa, Catalpa species
- Cactaceae (Cactus family)
  - Saguaro, Carnegiea gigantea
- Cannabaceae (Cannabis family)
  - Hackberry, Celtis species
- Cornaceae (Dogwood family)
  - Dogwood, Cornus species
- Dipterocarpaceae family
  - Garjan Dipterocarpus species
  - Sal Shorea species
- Ericaceae (Heath family)
  - Arbutus, Arbutus species
- Eucommiaceae (Eucommia family)
  - Eucommia Eucommia ulmoides
- Fabaceae (Pea family)
  - Acacia, Acacia species
  - Honey locust, Gleditsia triacanthos
  - Black locust, Robinia pseudoacacia
  - Laburnum, Laburnum species
  - Pau Brasil, Brazilwood, Caesalpinia echinata
- Fagaceae (Beech family )
  - Chestnut, Castanea species
  - Beech, Fagus species
  - Southern beech, Nothofagus species
  - Tanoak, Lithocarpus densiflorus
  - Oak, Quercus species
- Fouquieriaceae (Boojum family)
  - Boojum, Fouquieria columnaris
- Hamamelidaceae (Witch-hazel family)
  - Sweetgum, Liquidambar species
  - Persian Ironwood, Parrotia persica
- Juglandaceae (Walnut family)
  - Walnut, Juglans species
  - Hickory, Carya species
  - Wingnut, Pterocarya species
- Lauraceae (Laurel family)
  - Cinnamon Cinnamomum zeylanicum
  - Bay Laurel Laurus nobilis
  - Avocado Persea americana
- Lecythidaceae (Paradise nut family)
  - Brazil Nut Bertholletia excelsa
- Lythraceae Loosestrife family
  - Crape-myrtle Lagerstroemia species
- Magnoliaceae (Magnolia family)
  - Tulip tree, Liriodendron species
  - Magnolia, Magnolia species
- Malvaceae (Mallow family; including Tiliaceae and Bombacaceae) Bombacaceae
  - Baobab, Adansonia species
  - Silk-cotton tree, Bombax species
  - Bottletrees, Brachychiton species
  - Kapok, Ceiba pentandra
  - Durian, Durio zibethinus
  - Balsa, Ochroma lagopus
  - Cacao (cocoa), Theobroma cacao
  - Linden (Basswood, Lime), Tilia species
- Meliaceae (Mahogany family)
  - Neem, Azadirachta indica
  - Bead tree, Melia azedarach
  - Mahogany, Swietenia mahagoni
- Moraceae (Mulberry family)
  - Fig, Ficus species
  - Mulberry, Morus species
- Myristicaceae (Nutmeg family)
  - Nutmeg, Mysristica fragrans
- Myrtaceae (Myrtle family)
  - Eucalyptus, Eucalyptus species
  - Myrtle, Myrtus species
  - Guava, Psidium guajavaGuava in flower]]
- Nyssaceae (Tupelo family; sometimes included in Cornaceae)
  - Tupelo, Nyssa species
  - Dove tree, Davidia involucrata
- Oleaceae (Olive family)
  - Olive, Olea europaea
  - Ash, Fraxinus species
- Paulowniaceae (Paulownia family)
  - Foxglove Tree, Paulownia species
- Platanaceae (Plane family)
  - Plane, Platanus species
- Rhizophoraceae (Mangrove family)
  - Red Mangrove, Rhizophora mangle
- Rosaceae (Rose family)
  - Rowans, Whitebeams, Service Trees Sorbus species
  - Hawthorn, Crataegus species
  - Pear, Pyrus species
  - Apple, Malus species
  - Almond, Prunus dulcis
  - Peach, Prunus persica
  - Plum, Prunus domestica
  - Cherry, Prunus species
- Rubiaceae (Bedstraw family)
  - Coffee, Coffea species
- Rutaceae (Rue family)
  - Citrus, Citrus species
  - Cork-tree, Phellodendron species
  - Euodia, Tetradium species
- Salicaceae (Willow family)
  - Aspen, Populus species
  - Poplar, Populus species
  - Willow, Salix species Willow
- Sapindaceae (including Aceraceae, Hippocastanaceae) (Soapberry family)
  - Maple, Acer species
  - Buckeye, Horse-chestnut, Aesculus species
  - Mexican Buckeye, Ungnadia speciosa
  - Lychee, Litchi sinensis
  - Golden rain tree, Koelreuteria paniculata
- Sapotaceae (Sapodilla family)
  - Gutta-percha, Palaquium species
  - Tambalacoque, or "dodo tree", Sideroxylon grandiflorum, previously Calvaria major
- Simaroubaceae family
  - Tree of heaven, Ailanthus species
- Theaceae (Camellia family)
  - Gordonia, Gordonia species
  - Stuartia, Stuartia species
- Thymelaeaceae (Thymelaea family)
  - Ramin, Gonystylus species
- Ulmaceae (Elm family)
  - Elm, Ulmus species
  - Zelkova, Zelkova species
- Verbenaceae family
  - Teak, Tectona species

Monocotyledons (Liliopsida)

Monocotyledon
- Agavaceae (Agave family)
  - Cabbage tree, Cordyline australis
  - Dragon tree, Dracaena draco
  - Joshua tree, Yucca brevifolia
- Arecaceae (Palmae) (Palm family)
  - Areca Nut, Areca catechu
  - Coconut Cocos nucifera
  - Date Palm, Phoenix dactylifera
  - Chusan Palm, Trachycarpus fortunei
- Poaceae (grass family)
  - Bamboos Poaceae subfamily Bambusoideae
- Note that banana 'trees' are not actually trees; they are not woody nor is the stalk perennial.

Conifers (Pinophyta; softwood trees)


- Araucariaceae (Araucaria family)
  - Araucaria, Araucaria species
  - Kauri, Agathis species
- Cupressaceae (Cypress family)
  - Cypress, Cupressus species
  - Cypress, Chamaecyparis species
  - Juniper, Juniperus species
  - Alerce or Patagonian cypress, Fitzroya cupressoides
  - Sugi, Cryptomeria japonica
  - Coast Redwood, Sequoia sempervirens
  - Giant Sequoia, Sequoiadendron giganteum
  - Dawn Redwood, Metasequoia glyptostroboides
  - Bald Cypress, Taxodium distichum
- Pinaceae (Pine family)
  - White pine, Pinus species
  - Pinyon pine, Pinus species
  - Pine, Pinus species
  - Spruce, Picea species
  - Larch, Larix species
  - Douglas-fir, Pseudotsuga species
  - Fir, Abies species
  - Cedar, Cedrus species
- Podocarpaceae (Yellowwood family)
  - African Yellowwood, Afrocarpus falcatus
  - Totara, Podocarpus totara
- Sciadopityaceae
  - Kusamaki, Sciadopitys species
- Taxaceae (Yew family)
  - Yew, Taxus species

Ginkgos (Ginkgophyta)


- Ginkgoaceae (Ginkgo family)
  - Ginkgo, Ginkgo biloba

Cycads (Cycadophyta)


- Cycadaceae family
  - Ngathu cycad, Cycas angulata
- Zamiaceae family
  - Wunu cycad, Lepidozamia hopei

Ferns (Pterophyta)


- Cyatheaceae and Dicksoniaceae families
  - Tree ferns, Cyathea, Alsophila, Dicksonia (not a monophyletic group)

Life stages

The life cycles of trees, especially conifers, are divided into the following stages in forestry for survey and documentation purposes: # Seed # Seedling: the above ground part of the embryo that sprout from the seed # Sapling: After the seedling reaches 1m tall, and until it reaches 7cm in stem diameter # Pole: young trees from 7-30cm diameter # Mature tree: over 30cm diameter, reproductive years begin # Old tree: dominate old growth forest; height growth slows greatly, with majority of productivity in seed production # Overmature: dieback and decay become common # Snag: standing dead wood # Log/debris: fallen dead wood Tree diameters are measured at height of between 1.3-1.5m above the highest point on the ground at its base. The 7cm diameter definition is economically based, from the smallest saleable stem size (for paper production, etc), and the 30cm diameter is the smallest base diameter for sawlogs. Each stage may be uniquely perceptive to different pathogens and suitable for especially adapted arboreal animals.

See also


- Arboretum
  - Pinetum
- Arboriculture (the care of trees)
- Bonsai
- Christmas tree
- Dendrology (the study of trees)
  - Dendrochronology
  - Dendroclimatology
- Ecology
  - Tree-line
- Forestry
  - Deforestation
  - Plantation
  - Urban Forestry
  - Woodland management
- Fruit trees
- List of famous trees
- List of garden plants
- Plants
- Prehistoric plants
- Tree climbing
- Trees in mythology
- Trees of the world
  - Trees of Britain and Ireland
  - Trees of Canada
  - List of U.S. state trees
  - Trees of The Caribbean Basin
  - Trees of Iran
  - List of trees of New Zealand
- Wood
  - List of woods

External links


- [http://www.globaltrees.org/default.asp GLOBAL TREES .org] Campaigning to save the world's most threatened trees
- [http://www.fssca.net/romero/ Romero Memorial Tree Project] Plant a tree in El Salvador

Bibliography


- Pakenham, T. (2002). Remarkable Trees of the World. ISBN 0297843001
- Pakenham, T. (1996). Meetings with Remarkable Trees. ISBN 0297832557 Category:Plants
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- Category:Botany Category: plant morphology ms:Pokok ja:木 simple:Tree th:ต้นไม้

Fabaceae


Faboideae
Caesalpinioideae
Mimosoideae
References
[http://pgrc3.agr.ca/cgi-bin/npgs/html/family.pl?440 GRIN-CA] 2002-09-01 The Family Fabaceae sensu latu (also as Family Leguminosae) is a grouping of plants in the Order Fabales, and one of the largest families of flowering plants with 650 genera and over 18,000 species. These plants are commonly called legumes or pulses and the family contains some of our most valuable food crops, such as beans, peas, peanuts, soybeans, and lentils. Other members of the family are important sources of animal feed or green manure, such as lupins, clover, alfalfa, cassia, and soybean. Some genera such as Laburnum, Robinia, Gleditsia, Acacia, Mimosa, and Delonix are ornamental trees and shrubs. Still other members of the family have medicinal or insecticidal properties (for instance Derris) or yield important substances like gum arabic, tannin, dyes, or resins. Then there is kudzu, an east Asian species originally planted in the U.S. southeast for soil improvement and as a cattle feed, that has become a notorious invasive weed that tends to grow over everything. The use of the name Fabaceae is ambiguous, since it was used to represent the group faboideae for many years. Many specialists, especially in herbaria and floristics research, still use the old name of the family, Leguminosae, on order to avoid confusion. All members of this family have five-petaled flowers in which the superior ovary ripens to form a "pod", technically called a legume, whose two sides split apart, releasing the seeds which are attached to one or both seams. The legumous plants are classified into three subfamilies, sometimes raised to the rank of family in the order Fabales, on the basis of flower morphology (specifically, petal shape):
- Faboideae (Fabaceae sensu strictu), previously called Papilionoideae: One petal is large and has a crease in it, the two adjacent petals are on the sides, and the two bottom petals are joined together at the bottom, forming a boat-like structure.
- Caesalpinioideae (Caesalpiniaceae): The flowers are zygomorphic, but are very variable, e.g. closely resembling Faboideae flowers in Cercis, while symmetrical with five equal petals in Bauhinia.
- Mimosoideae (Mimosaceae): The petals are small, and are frequently globose or spicate and the stamens are the most showy part of the flower.

Nitrogen fixation

A significant characteristic of legumes is that they host bacteria in their roots, within structures called root nodules. These bacteria known as rhizobia have the ability to take nitrogen gas (N2) out of the air and convert it to a form of nitrogen that is usable to the host plant ( NO3- or NH3 ). This process is called nitrogen fixation. The legume, acting as a host; and rhizobia, acting as a provider of usable nitrate, form a symbiotic relationship. symbiotic

External link


- [http://www.ildis.org/ International Legume Database & Information Service] Category:Fabaceae Category:Legumes Category:Plant families Category:Nitrogen metabolism ja:マメ科

River

:For the Second World War frigate class, see River class frigate. For the state of Nigeria, see Rivers State. MyScene.]] A river is a large natural waterway. It is a specific term in the vernacular for large streams, stream being the umbrella term used in the scientific community for all flowing natural waterways. In the vernacular, stream may be used to refer to smaller streams, as may creek, run, fork, etc. Passage via a river or stream is the usual way rainfall on land finds its way to the ocean or other large body of water such as a lake. A river consists of several basic parts, originating from headwaters or a spring at the source, that flow into the main stream. Smaller side streams that join the river are tributaries. Water flow is normally confined to a channel, with a bottom or bed between banks. The lower end of a river is its base level, commonly called its mouth, a river typically widens at its end and forms what is known as a river delta or estuary.

Topography

estuary.]]A river conducts water by constantly flowing perpendicular to the elevation curve of its bed, thereby converting the positional energy of the water into kinetic energy. Where a river flows over relatively flat areas, the river will meander: start to form loops and snake through the plain by eroding the river banks. Loops that are formed are sometimes cut off, forming a shorter river channel and leaving a remnant, oxbow lake. Rivers that carry large amounts of sediment develop conspicuous deltas at their mouths. Rivers whose mouths are in saline tidal waters may form estuaries. There are 4 main types of rivers. These types are:
- Youthful river - a river with a steep gradient that has very few tributaries and flows quickly. Its channels erode deeper rather than wider.
- Mature river - a river with a gradient that is less steep than those of youthful rivers and flows more slowly than youthful rivers. A mature river is fed by many tributaries and has more discharge than a youthful river. Its channels erode wider rather than deeper.
- Old river - a river with a low gradient and low erosive energy. Old rivers are characterized by flood plains.
- Rejuvenated river - a river with a gradient that is raised by the earth's movement. Where a river descends quickly over sloped topography, rapids with whitewater or even waterfalls occur. Rapids are often used for recreational purposes (see Whitewater kayaking). Waterfalls are sometimes used as sources of energy, via watermills and hydroelectric plants. Rivers begin at their source in higher ground, either rising from a spring, forming from glacial meltwater, flowing from a body of water such as a lake, or simply from damp, boggy places where the soil is waterlogged. They end at their base level where they flow into a larger body of water, the sea, a lake, or as a tributary to another (usually larger) river. In arid areas rivers sometimes end by losing water to evaporation and percolation into dry, porous material such as sand, soil, or pervious rock. The area drained by a river and its tributaries is called its watershed or catchment basin. (Watershed is also used however to mean a boundary between catchment basins.) Starting at the mouth of the river and following it upstream as it branches again and again the resulting river network forms a dendritic (tree-like) structure that is an example of a natural random fractal.

Biology

The flora and fauna of rivers are much different from those of the ocean because the water is fresh (non-salty). Living things in a river must be adapted to the current of the moving water.

Pollution

Human pollution of rivers is common, and very few rivers in the world today are clean of man-made substances. The most common pollutant is sewage piped into rivers, but chemical pollution is also common, and industrial accidents (and/or negligence) account for much of the destruction of riparian biomes. Heated water dumped into rivers by power plants and factories also affects river life.

Navigation

The Rhine is the busiest river in the world for transport ships. Inland vessels use the river to reach the major cities in Germany, Eastern France and Switzerland to transport bulk goods, liquids, containers AND passengers into the hinterland of the Port of Rotterdam and the ports of Amsterdam and Antwerp. Many millions of tons of goods are transported upstream yearly from these three sea ports to the industries near Nijmegen, Duisburg, Düsseldorf, Neuss, Köln, Koblenz, Mainz, Mannheim, Karlsruhe, Strasbourg, Colmar, Mulhouse and Basel. The lower part of the river is navigable for the largest inland vessels (up to 135 meters long and 17 meters wide) with an available depth of more than 2,50 even at the lower water levels. The further upstream, the more depth restrictions: at low water periods draught of ships is often limited to 1,90 m. for the stretch around Bingen (between the mouths of the Mosel and the Main). Upstream from Karlsruhe the Rhine is the border between France and Germany. The French have canalized the river by means of a series of hydropower dams and double ship locks, thus ensuring a year round navigable depth of 3.50 meters. (Source: NoorderSoft Waterways Database)

Dams

In places where the elevation changes of a river are great, dams for hydroelectric plants and other purposes are often built. This disrupts the natural flow of the river, and creates a lake behind the dam. Often the building of dams affects the whole of the river, even the part above the dam, as migrating fish are hindered (see fish ladder), waterflow is no longer bounded by seasonal changes and sediment flow is blocked. Dams are useful in many ways, such as providing HEP, acting as regulator of river flow so as to regulate the occurrence of flooding, which is especially important to wet-rice agriculture, and also to improve navigation and transport on the river. Often, dams such as Hoover Dam along Colorado River become famous tourist attractions. However, critics of dams, especially 'Green' advocates, argue that dams remove upper-river biodiversity such as through deforestation and forced migration of rural villages and indigenous tribes. Furthermore, trapping of river sediments behind the dams lead to salination and loss of nutrients for down-water fish. It also raises concern of eathquakes due to instablity of incompetent dams which have to support thousands of tonnes of sediments behind them. One very famous, and problematic, dam is the Aswan High Dam in the Nile.

Flooding

Flooding is a natural part of a river's cycles. Human activity, however, has upset the natural way flooding occurs by walling off rivers and straightening their courses. Removal of bogs, swamps and other wetlands in order to produce farmland has reduced the absorption zones for excess water and made floods into sudden disasters rather than gradual increases in water flow. In ancient Egypt, life was made possible through the floods of the Nile and the accompanying silt and sediment which enriched the fields with fresh nutrients. Nowadays, since people have built on these floodplains, floods are disasters, causing untold property loss each year. Human interference in the form of deforestation can also worsen conditions. The removal of vegetation leads to a reduction in Interception (vegetation stopping precipitation) and the 'weakening' of soil since plant roots no longer hold it together. As a result there is a reduced Infiltration capacity (how much water the soil can hold) and greater infiltration (precipitation going into the ground). This leads to faster soil saturation and therefore greater overland flow (also known as surface run off) and therefore, there are flash floods as the lag time decrease.

Logjams

Logjams are barriers within rivers, created by dead and uprooted trees. Over time, the obstruction prevents further logs to bypass, resulting in the creation of new network channels. According to author David R. Montgomery in his book, King of Fish, a logjam also causes water to buildup within a small space, forming peaceful pools within the main channel for young salmon to live within. The existence of these deep pools along with the complex web of channels creates an ideal salmon habitat. Today, many believe that the rebuilding of salmon runs is contingent upon reproducing the same environment shaped by logjams. As a result, many scientists have attempted to recreate artificial logjams. Marc Duboiski and Mike Ramsey of the Salmon Recovery Funding board staff, George Pess of the National Marine Fisheries Service, and Kevin Bauersfeld of Washington Department of Fish and Wildlife have prepared the Report to the Salmon Recovery Funding Board On the Engineered Log Jam (ELJ) Workshop ([http://iac.wa.gov/Documents/SRFB/Log_Jam_Report.pdf#search='log%20jams%20and%20salmon']), with the hope of mimicking natural logjams. Report to the Salmon Recovery Funding Board On the Engineered Log Jam (ELJ) Workshop."]]

Management

In its natural state a river may be inconvenient to man in a variety of ways. Rivers in inhabited areas have therefore been managed or controlled to make them more useful and less disruptive to human activity.
- The river channel may be dredged to make it deeper for navigation or to prevent flooding.
- Dams (see above) or weirs may be built to control the flow, store water, or extract energy.
- Levees may be built to prevent flooding.
- Sluice gates provide a means of controlling flow and adjusting river levels.
- floodways may be added to draw off excess river water in times of flood.
- Canals connect rivers to one another for water transfer or navigation.
- River courses may be modified to improve navigation, or straightened to increase the flow rate. River management is an ongoing activity as rivers tend to 'undo' the modifications made by man. Dredged channels silt up, sluice mechanisms deteriorate with age, levees and dams may suffer seepage or catastrophic failure.

River lists

(See also :Category:Lists of rivers.)

The world's ten longest rivers

It is difficult to measure the length of a river, mainly because rivers have a fractal property, which means that the more precise the measure, the longer the river will seem. Also, it's hard to state exactly where a river begins or ends, as very often, upstream, rivers are formed by seasonal streams, swamps, or changing lakes. This is an average measurement. # Nile (6,690 km) # Amazon (6,400 km) # Yangtze (Chang Jiang) (6,380 km) # Mississippi-Missouri (6,270 km) # Ob-Irtysh (5,570 km) # Huang He (Yellow) (5,464 km) # Amur (4,410 km) # Congo (4,380 km or 4,670 km). (The source of this river is disputed.) # Lena (4,260 km) # Mackenzie (4,240 km) For a longer list see Longest rivers. This also gives more information on measuring river lengths.

Well-known rivers (in alphabetic order)


- Aa - multiple rivers in Europe
- Amazon - largest river in the world
- American
- Amu Darya
- Amur - principal river of eastern Siberia
- Arkansas - major tributary of Mississippi River
- Arno - river through Florence
- Arvandrud (Shatt al-Arab) the large border river between Iran and Iraq.
- Brahmaputra - principal river in North East India & Tibet
- Chao Phraya - principal river of Thailand
- Colorado (Argentina)
- Colorado (U.S.) - principal river of American West
- Columbia - principal river of Pacific Northwest
- Congo - principal river of central Africa
- Danube - principal river of central and southeastern Europe
- De La Plata - the widest river in the world. South America
- Ebro - river in northwest Spain
- Elbe - major German river, Hamburg is situated on it
- Euphrates - twin principal river of Mesopotamia(Iraq)
- Ganges - principal river of India
- Han-gang - river of Seoul
- Helmand River - Principle river of (Afghanistan)
- Hari Rud (Afghanistan)
- Huang He (Yellow) - principal river of China
- Hudson - principal river of New York
- Indus - principal river of Pakistan
- Jordan - principal river of Israel
- Karun - principal (navigable) river of southern Iran.
- Kaveri - principal river of South India
- Lena - principal river of northeastern Siberia
- Mackenzie - longest river in Canada
- Magdalena - principal river of Colombia
- Main - river in Germany
- Mekong - principal river of Southeast Asia
- Mersey - river on which sits the English city of Liverpool
- Meuse - principal river of the southern provinces of the Netherlands and eastern Belgium.
- Mississippi - principal river of central United States
- Missouri - principal river of the Great Plains
- Murray - principal river of southeastern Australia
- Niger - principal river of west Africa
- Nile - Possibly the longest river in the world (or second after the Amazon)
- Ob - large river of Siberia
- Odra - major river in Eastern Europe
- Ohio - largest river between Mississippi and Appalachians
- Orinoco - principal river of Venezuela
- Parana - major South American river
- Paraguay - principal tributary of Parana river and major South American river in Brazil, Bolivia, Paraguay and Argentina
- Po - principal river of Italy
- Potomac River - principal river of the District of Columbia in the United States
- Rhine - principal river of northwestern Europe
- Rhône - principal river of southern France
- Rio Grande - border between United States and Mexico
- Saint Lawrence - drains Great Lakes
- Seine - river of Paris
- Segura- in southeast Spain
- Severn- longest river in Great Britain
- Shinano-gawa - longest river in Japan
- Snake - largest tributary to the Columbia river in Washington
- Tajo - largest river in the Iberian Peninsula
- Tay - largest river in Scotland
- Thames - river of London
- Tiber - river of Rome
- Tigris - twin principal river of Mesopotamia(Iraq)
- Tonegawa - largest river in Japan
- Vistula - principal river of Poland
- Volga - principal river of Russia
- Yangtze (Chang Jiang) - longest river in China
- Yenisei - large river of Siberia
- Yukon - principal river of Alaska and Yukon Territory
- Zambezi - principal river of southeastern Africa

Other lists


- List of waterways
- List of rivers by continent
  - List of rivers of Europe
    - Rivers of the United Kingdom
  - List of rivers of Asia
  - List of rivers of Africa
  - List of rivers of Australia
  - List of rivers of New Zealand
  - List of rivers of the Americas
  - List of rivers of Oceania
- List of river name etymologies

Rivers in myth and fiction

Real rivers


- The Thames in Edward Rutherfurd's London.
- The Thames in Jerome K. Jerome's Three Men in a Boat.
- The Thames and the Congo in Joseph Conrad's Heart of Darkness.
- The Mississippi in Mark Twain's Huckleberry Finn.
- The River Liffey through Dublin in James Joyce's Finnegans Wake.

Mythological rivers


- In Greek mythology, the Acheron, Cocytus, Phlegethon, Lethe and Styx (the five rivers of Hades); and the Eridanus.
- The Alph, an underground river imagined by various mystics and mentioned in Coleridge's poem Kubla Khan.
- The Sambation river stops flowing every Saturday.

Fictional rivers


- River Ankh traversing the city of Ankh-Morpork in Terry Pratchett's Discworld series.
- Chocolate river in Willy Wonka and the Chocolate Factory.
- River Djel in the country of Djelibeybi in Terry Pratchett's Discworld series.
- The River in the Riverworld novels of Philip José Farmer.
- Rivers of Middle-earth in various works of J. R. R. Tolkien.

See also


- Aquaduct
- Canal
- Drought
- Water dispute

Crossings

Rivers may be crossed by:
- bridges
- ferries
- fords
- tunnels.

Transport


- barge
- riverboat
- sailing
- towpath

External links


- [http://www.srbc.net/about.htm Management: River Basin Commissions]. Category:Bodies of water Category:Geomorphology zh-min-nan:Hô ja:川 ko:강 ms:Sungai simple:River th:แม่น้ำ

Creek

Creek can be:
- A native American tribe, see Creek people
- The language of that tribe, see Creek language
- In US, Canadian and Australian usage, a waterflow, smaller than a river, see Creek (stream)
- In UK and Indian usage, a tidal watercourse, usually drying to little or no flow at low tide, see Creek (tidal)
- A helicopter: the Bell TH-67 Creek See also:
- Creek mythology

Carnarvon, Western Australia

Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town.

History

The town was founded in 1883, initially as a port and supply centre for the surrounding region, and is the administrative centre for the Carnarvon Shire.

Population

The population of Carnarvon is 6622 (ABS estimate 2003).

Main industries

ABS Main industries of the area have included wool, agriculture, particularly fruit, and more recently, tourism. During the 1960s, NASA set up a tracking station nearby to support the Apollo space program. The tracking station was closed in the mid 1970s, however the site remains, and is now a tourist attraction in its own right.

Education

There are 5 school in the town, 3 Government run and 2 Inderpendant. These Schools are: St Mary's Star of the Sea Catholic School, Carnarvon Senior High School, East Carnarvon Primary School, Carnarvon Primary School, Carnarvon Christian School and Carnarvon School of the Air.

Korean Star

On the 20th of May 1988 the bulk carrier Korean Star ran aground in bad weather near Cape Cuvier, within the port limits of Carnarvon. Around 600 tonnes of fuel oil were spilled into the ocean. Damage was limited to 10km of remote beaches and coastline. The ship was not salvaged and left grounded, however very little of the wreck remains to be seen.

External links


- [http://www.carnarvon.wa.gov.au/| Shire of Carnarvon] Category:Towns in Western Australia Category:Local Government Areas of Western Australia

Phyllode

Phyllodes are modified petioles or leaf stems. In some plants, these become flattened and widened, while the leaf itself becomes reduced or vanishes altogether. Thus the phyllode comes to serve the purpose of the leaf. They are common in the genus Acacia, especially the Australian species, at one time put in Acacia subg. Phyllodineae. Sometimes, especially on younger plants, partially formed phyllodes bearing reduced leaves can be seen. Category: plant morphology

Minni ritchi

Minni ritchi is a type of reddish brown bark that continuously peels in small curly flakes, leaving the tree looking like it has a coat of red curly hair. Brooker and Kleinig (1990) formally described it as a bark type in which "the outer rich, red-brown smooth bark splits both longitudinally and horizontally, the free edges rolling back without completely detaching to expose new green bark beneath". A number of species of Acacia have minni ritchi bark. These include:
- Acacia curranii
- Acacia cyperophylla, commonly known as creekline miniritchie
- Acacia gracillima
- Acacia grasbyi, commonly known as miniritchie
- Acacia monticola
- Acacia trachycarpa

References


- Category:Australian plants Category:Plant anatomy

Category:Flora of Western Australia

Western Australia, Flora of Category:Western Australia

Category:Acacia

Category:Mimosoideae Category:Trees

Baker plan

The Baker Plan is a United Nations iniative to grant Western Sahara self-determination. It was intended to substitute the Settlement Plan of 1991, which had been further detailed in the Houston Agreement of 1997. Western Sahara's occupation by Morocco since 1975 is challenged by Polisario guerillas living in exile in neighbouring Algeria. Since 1991 a cease-fire is in place, accepted by both parties under the assumption that the UN would organize a referendum on independence. The 1991 referendum plan was however stalled due to disagreements on voter eligibility (Morocco demanding inclusion of its settlers, brought into the territory to out-number the Saharawi indigenous population), and by the late nineties Morocco was openly declaring the referendum a "dead option"; the cease-fire held due to foreign pressures on the Polisario. The Baker plan aims at instituting Saharan self-rule in a "Western Sahara Authority" for a period of five years, whereafter the referendum is to be held, with Moroccan settlers controversially allowed the vote. The first version of the plan, called Baker I, was delivered by UN special envoy James Baker in 2000, but both parties refused to accept it. The second version (Baker II) included minor changes, notably provisions as to how the Saharan autonomy was to be safe-guarded from Moroccan pressures, pleasing the Polisario, but also adding a third option of "permanent autonomy" to the ballot, thereby indulging Morocco. This version of the plan was unanimously put forward by the Security Council in mid-2003. It was accepted by the Polisario but rejected outright by Morocco, on the basis that the plan "questions Moroccan territorial integrity". This prompted Baker to resign, the second UN envoy to Western Sahara to do so, claiming there was no longer any feasible way to implement the peace agreement provisions. He has since then stated that Morocco showed no interest in implementing the UN decisions and will not do so if it stands a chance to lose in the referendum. Since early 2005 the UN Secretary General stopped referring to the plan in his reports, and by now it seems largely dead. No replacement plan exists, however, and worries persist that the political vacuum will result in renewed fighting. Category:Western Sahara

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