:: wikimiki.org ::

Temperate Rain Forest

Temperate rain forest

Temperate rain forests are coniferous or broadleaf forests that occur in the mid-latitudes in areas of high rainfall. Temperate rain forests are distinguished from other temperate forests by a few factors:
- Rainfall: high rainfall (minimum 2000-3000 mm/year, depending on latitude), usually from moisture-laden winds off the ocean.
- Proximity to the ocean: temperate rain forests depend on the proximity to the ocean to moderate seasonal variations in temperature, creating milder winters and cooler summers than continental-climate areas. Many temperate rain forests have summer fogs that keep the forests cool and moist in the hottest months.
- Coastal mountains: temperate rain forests occur where mountains ranges are close to the coast; coastal mountains increase rainfall on the ocean-facing slopes. Temperate rain forests may be predominantly coniferous, broadleaf, or mixed forests, and occur in Temperate broadleaf and mixed forests and Temperate coniferous forests ecoregions. The temperate coniferous rain forests sustain the highest levels of biomass in any terrestrial ecosystem and are notable for trees of massive proportions, including Coast Redwood (Sequoia sempervirens), Giant Sequoia (Sequoiadendron giganteum), Coast Douglas-fir (Pseudotsuga menziesii), Sitka Spruce (Picea sitchensis), Alerce (Fitzroya cupressoides) and Kauri (Agathis australis). These forests are quite rare, occurring in small areas of Western North America, southwestern South America and northern New Zealand. Temperate forests cover a large part of the globe, but temperate rain forests only occur in seven regions around the world; the Pacific temperate rain forests of North America, the Valdivian and Magellanic temperate rain forests of southwestern South America, the Colchian rain forests of the eastern Black Sea region (Turkey and Georgia), the New Zealand temperate rain forests, the Tasmanian temperate rain forests, and pockets of rain forest in northwest Europe and southwest Japan.

Temperate Rain Forest Regions

Pacific temperate rain forests (Canada, United States)
The largest temperate rain forest zone on the planet, the Pacific temperate rain forests occur on west-facing coastal mountains along the Pacific coast of North America, from Kodiak Island in Alaska to northern California, and are part of the Nearctic ecozone. These rain forests occur in a number of ecoregions, which vary in their species composition, but are all predominantly conifers, sometimes with an understory of broadleaved trees and shrubs. Pacific temperate rain forests can be found in the Northern Pacific coastal forests, Queen Charlotte Islands, Vancouver Island, British Columbia mainland coastal forests, Central Pacific coastal forests, Central and Southern Cascades forests, Klamath-Siskiyou forests, and Northern California coastal forests ecoregions. The Northern California coastal forests are home to the Coast Redwood (Sequoia sempervirens), the world's tallest tree. Valdivian and Magellanic temperate rain forests (Chile, Argentina)
The temperate rain forests of South America are located on the Pacific coast of southern Chile, on the west-facing slopes of the southern Chilean coast range and the Andes Mountains down to the southern tip of South America, and are part of the Neotropic ecozone. The Valdivian rain forests are dominated by broadleaf southern beech (Nothofagus), but include many conifers as well. The Valdivian rain forests occur in the Valdivian temperate rain forests and Magellanic subpolar forests ecoregions. New Zealand temperate rain forests (New Zealand)
The temperate rain forests of New Zealand occur on the western shore of New Zealand's South Island. The forests are made up of coniferous podocarps and broadleaf evergreen trees; the podocarps are dominant at lower elevations, while southern beech becomes dominant on higher slopes and in the cooler southernmost rain forests. Ecoregions include the Fiordland temperate forests and Westland temperate forests. Australian temperate rain forests (Australia)
Tasmania's west coast is home to the Tasmanian temperate rain forests ecoregion. They are mixed forests, with broadleaf southern beech and conifers, including Huon Pine (Lagarostrobos franklinii), and King Billy Pine (Athrotaxis selaginoides). Temperate rainforests also occur in Victoria's Otway Ranges, the Strzelecki Ranges, East Gippsland and south-east New South Wales. Colchian rain forests (Georgia, Turkey)
The Colchian rain forests are found around the southeast corner of the Black Sea, and are part of the Euxine-Colchic deciduous forests ecoregion, together with the drier Euxine forests further west. The Colchian rain forests are mixed, with deciduous alder, hornbeam, Oriental Beech (Fagus orientalis), and chestnut together with evergreen Nordmann Fir (Abies nordmanniana, the tallest tree in Europe at 78m), Caucasian Spruce (Picea orientalis) and Scots Pine (Pinus sylvestris). Japanese temperate rain forests (Japan)
Southwestern Japan. Northwest Europe temperate rain forests
Scotland, Ireland, Norway, Iceland; mostly gone. However, parts of the Scandinavian coastal conifer forests in coastal areas of Central Norway are still left. zh-min-nan:Un-tài ú-lîm

External links

- [http://www.cotf.edu/ete/modules/temprain/temprain.html Teacher Pages: Temperate Rainforest (Wheeling University)] Category:Terrestrial biomes

Conifer

Cordaitales †
Pinales
  Pinaceae - Pine family
  Araucariaceae - Araucaria family
  Podocarpaceae - Yellow-wood family
  Sciadopityaceae - Umbrella-pine family
  Cupressaceae - Cypress family
  Cephalotaxaceae - Plum-yew family
  Taxaceae - Yew family
Vojnovskyales †
Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being trees with just a few being shrubs. Typical examples of conifers include cedars, cypresses, douglas-firs, firs, junipers, kauris, larches, pines, redwoods, spruces, and yews. Species of conifers can be found growing naturally in almost all parts of the world, and are frequently dominant plants in their habitats, as in e.g. the taiga. Conifers are of immense economic value, primarily for timber and paper production; the wood of conifers is known as softwood.

Taxonomy and naming

The division name Pinophyta conforms with the rules of the ICBN, which state (Art 16.1) that the names of higher taxa in plants (above the rank of family) are either based on the name of the type genus, in this case, Pinus (pines), or are descriptive. In the latter case the name for the conifers is Coniferae (Art 16 Ex 2), which is in widespread use as well. Older scientific names (no longer allowed) are Coniferophyta and Coniferales. In an older, broader sense of the name, the conifers were often considered equivalent to the Gymnosperms, although this grouping is polyphyletic as it includes distinct, only distantly related plants like the cycads and ginkgos not in the Pinophyta, but excludes the Magnoliophyta (flowering plants), equally or perhaps more closely related. The division contains just one class of living plants, class Pinopsida. Subdivision of the conifers into two or more orders has been proposed from time to time. The most commonly seen in the past was a split into two orders, Taxales (Taxaceae only) and Pinales (the rest), but recent genetic evidence has shown that this interpretation leaves the Pinales without Taxales as polyphyletic, and the latter order is no longer regarded as distinct. A more accurate division would be to split the division into three orders, Pinales containing only Pinaceae, Araucariales containing Araucariaceae and Podocarpaceae, and Cupressales (including Taxales) containing the remaining families, but there has not been any significant support for any division, with the majority of opinion preferring retention of all the families within a single order Pinales, despite their antiquity and diverse morphology. polyphyletic The conifers are now accepted as comprising six to eight families, with a total of 65-70 genera and 600-650 species. The seven most distinct families are linked in the box above right and phylogenetic diagram left. In other interpretations, the Cephalotaxaceae may be better included within the Taxaceae, and some authors additionally recognise Phyllocladaceae as distinct from Podocarpaceae (in which it is included here). A further family Taxodiaceae was widely recognised in the past, but is now normally included within Cupressaceae. The conifers are an ancient group, with a fossil record extending back about 300 million years to the Paleozoic in the late Carboniferous period; even many of the modern genera are recognisable from fossils 60-120 million years old. Other classes and orders, now long extinct, also occur as fossils, particularly from the late Paleozoic and Mesozoic eras. Fossil conifers included many diverse forms, the most dramatically distinct from modern conifers being some herbaceous conifers with no woody stems. Major fossil orders of conifers or conifer-like plants include the Cordaitales, Vojnovskyales, Voltziales and perhaps also the Czekanowskiales (possibly more closely related to the Ginkgophyta).

Morphology

All living conifers are woody plants, and most are trees, the majority having monopodial growth form (a single, straight trunk with side branches). The size of mature conifers varies from less than one metre, to over 100 metres. The world's tallest, largest, thickest and oldest living things are all conifers. The tallest is a Coast Redwood (Sequoia sempervirens), with a height of 112.34 metres. The largest is a Giant Sequoia (Sequoiadendron giganteum), with a volume 1486.9 cubic metres. The thickest, or tree with the greatest trunk diameter, is a Montezuma Cypress (Taxodium mucronatum), 11.42 metres in diameter. The oldest is a Great Basin Bristlecone Pine (Pinus longaeva), 4,700 years old.

Foliage

Great Basin Bristlecone Pine (Pseudotsuga menziesii)]] Great Basin Bristlecone Pine (Chamaecyparis lawsoniana); scale in mm]] The leaves of many conifers are long, thin and needle-like, but others, including most of the Cupressaceae and some of the Podocarpaceae, have flat, triangular scale-like leaves. Some, notably Agathis in Araucariaceae and Nageia in Podocarpaceae, have broad, flat strap-shaped leaves. In the majority of conifers, the leaves are arranged spirally, exceptions being most of Cupressaceae and one genus in Podocarpaceae, where they are arranged in decussate opposite pairs or whorls of 3 (-4). In many species with spirally arranged leaves, the leaf bases are twisted to present the leaves in a flat plane for maximum light capture (see e.g. photo of Grand Fir Abies grandis). Leaf size varies from 2 mm in many scale-leaved species, up to 400 mm long in the needles of some pines (e.g. Apache Pine Pinus engelmannii). The stomata are in lines or patches on the leaves, and can be closed when it is very dry or cold. The leaves are often dark green in colour which may help absorb a maximum of energy from weak sunshine at high latitudes or under forest canopy shade. Conifers from hotter areas with high sunlight levels (e.g. Turkish Pine Pinus brutia) often have yellower-green leaves, while others (e.g. Blue Spruce Picea pungens) have a very strong glaucous wax bloom to reflect ultraviolet light. In the great majority of genera the leaves are evergreen, usually remaining on the plant for several (2-40) years before falling, but three genera (Larix, Taxodium and Metasequoia) are deciduous, shedding the leaves in autumn and leafless through the winter. The seedlings of many conifers, including most of the Cupressaceae, and Pinus in Pinaceae, have a distinct juvenile foliage period where the leaves are different, often markedly so, from the typical adult leaves.

Reproduction

deciduous See conifer cones for a more detailed discussion. Most conifers are monoecious, but some are subdioecious or dioecious; all are wind-pollinated. Conifer seeds develop inside a protective cone called a strobilus (or, very loosely, "pine cones", which technically occur only on pines, not other conifers!). The cones take from four months to three years to reach maturity, and vary in size from 2 mm to 600 mm long. In Pinaceae, Araucariaceae, Sciadopityaceae and most Cupressaceae, the cones are woody, and when mature the scales usually spread open allowing the seeds to fall out and be dispersed by the wind. In some (e.g. firs), the cones disintegrate to release the seeds, and in others (e.g. the pines that produce pine nuts) the nut-like seeds are dispersed by birds (mainly nutcrackers and jays) which break up the specially adapted softer cones. Ripe cones may remain on the plant for a varied amount of time before falling to the ground; in some fire-adapted pines, the seeds may be stored in closed cones for up to 60-80 years, being released only when a fire kills the parent tree. jay In the families Podocarpaceae, Cephalotaxaceae, Taxaceae, and one Cupressaceae genus (Juniperus), the scales are soft, fleshy, sweet and brightly coloured, and are eaten by fruit-eating birds, which then pass the seeds in their droppings. These fleshy scales are (except in Juniperus) known as arils. In some of these conifers (e.g. most Podocarpaceae), the cone consists of several fused scales, while in others (e.g. Taxaceae), the cone is reduced to just one seed scale or (e.g. Cephalotaxaceae) the several scales of a cone develop into individual arils, giving the appearance of a cluster of berries. The male cones have structures called microsporangia which produce yellowish pollen. Pollen is released and carried by the wind to female cones. Pollen grains from living pinophyte species produce pollen tubes, much like those of angiosperms. When a pollen grain lands near a female gametophyte, it undergoes meiosis and fertilizes the female gametophyte. The resulting zygote develops into an embryo, which along with its surrounding integument, becomes a seed. Eventually the seed may fall to the ground and, if conditions permit, grows into a new plant. In forestry, the terminology of flowering plants has commonly though inaccurately been applied to cone-bearing trees as well. The male cone and unfertilized female cone are called "male flower" and "female flower", respectively. After fertilization, the female cone is term "fruit", which undergoes "ripening" (maturation).

Life cycle

# To fertilize the ovum, the male cone releases pollen that is carried on the wind to the female cone. # A fertilized female gamete (called a zygote) develops into an embryo. # Along with integument cells surrounding the embryo, a seed develops containing the embryo. # Mature seed drops out of cone onto the ground. # Seed germinates and seedling grows into a mature plant. # When mature, the adult plant produces cones.

Other facts

seed Although the total number of species is relatively small, conifers are of immense ecological importance. They are the dominant plants over huge areas of land, most notably the boreal forests of the northern hemisphere, but also in similar cool climates in mountains further south. Many conifers have distinctly scented resin, secreted to protect the tree against insect infestation and fungal infection of wounds. Fossilised resin hardens into amber.

External link

- [http://tolweb.org/tree?group=Conifers&contgroup=Spermatopsida ToLweb: Conifers] Category:Conifers ko:구과식물 ja:球果植物門

Rain forest

, Australia. ]] A rainforest is a forested biome with high annual rainfall. Tropical rainforests arise due to the Intertropical convergence zone, and temperate rainforests also exist. As well as prodigious rainfall, many rainforests are characterized by a high number of resident species and tremendous biodiversity. The largest tropical rainforests exist in the Amazon basin (the Amazon Rainforest), in the equatorial portions of Africa from Cameroon to the Democratic Republic of Congo; in much of southeastern Asia from Myanmar to Indonesia and Papua New Guinea; and also eastern Queensland, Australia. Outside of the tropics, temperate rainforests can be found in British Columbia, southeastern Alaska, western Caucasus (Ajaria region of Georgia), as well as in parts of the Balkans. It has been estimated that rainforests provide up to 40% of the oxygen found in the atmosphere and that the vegetation acts as an important consumer of atmospheric carbon. As such, many scientists feel that the rainforests are of vital importance within the global climate system.

Characteristics

Rainforests are characterized by high rainfall, with definitions setting minimum normal annual rainfall between 2,000 mm (about 100 inches or 200 centimetres) and 1700 mm (about 67 inches). The soil can be poor because high rainfall tends to leach out soluble nutrients. Rain forests are home to two-thirds of all the living animal and plant species on the planet. It has been estimated that many hundreds of millions of new species of plants, insects, and microorganisms are still undiscovered and as yet unnamed by science. Tropical rain forests are called the "jewel of the earth", the "Earth's lungs", and the "world's largest pharmacy" because of the large amount of natural medicines discovered there. Despite the growth of flora in a rainforest, the actual quality of the soil is quite poor. Oxisols, infertile, deeply weathered and severely leached, have developed on the ancient Gondwanan shields. Rapid bacterial decay prevents the accumulation of humus. The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits (e.g. bauxite). On younger substrates, especially of volcanic origin, tropical soils may be quite fertile. The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at ground level. This makes it possible for people and other animals to walk through the forest. If the leaf canopy is destroyed or thinned for any reason, the ground beneath is soon colonised by a dense tangled growth of vines, shrubs and small trees called jungle.

Trees

bauxite] There are several common characteristics of tropical trees. Tropical species frequently possess one or more of the following attributes not commonly seen in trees of higher latitudes. Many species have broad, woody flanges (buttresses) at the base of the trunk. Originally believed to help support the tree, now it is believed that the buttresses channel stem flow and its dissolved nutrients to the roots. Large leaves are common among trees of the C layer. Young individuals of trees destined for the B and A layers may also have large leaves. When they reach the canopy new leaves will be smaller. The large leaf surface helps intercept light in the sun-dappled lower strata of the forest. Drip tips facilitate drainage of precipitation off the leaf to promote transpiration. They occur in the lower layers and among the saplings of species of the emergent layer (A layer). Trees are often well connected in the canopy layer especially by the growth of woody climbers or lianas. Plants with epiphytic adaptations, allowing them to grow on top of existing trees in the competition for sunlight. Other characteristics that distinguish tropical species of trees from those of temperate forests include: Exceptionally thin bark, often only 1-2 mm thick. Usually very smooth, although sometimes armed with spines or thorns. Cauliflory, the development of flowers (and hence fruits) directly from the trunk, rather than at the tips of branches. Large fleshy fruits attract birds, mammals, and even fish as dispersal agents.

The canopy

Away from river banks, swamps and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation, as little sunlight penetrates to ground level. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 40% of all plant species, suggesting that perhaps half of all life on Earth could be found there. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, US naturalist, William Beebe declared that "another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles". True exploration of this habitat only began in the 1980's, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and the building of cranes and walkways planted on the forest floor.

The rainforest as a source of drugs

Tropical rain forests are called the 'world's largest pharmacy' because the large amount of natural medicines discovered there. Nearly half of the medicines that we use come from the rainforests. For example, rain forests are responsible for containing the "basic ingredients of birth control hormones, stimulants, and tranquilizing drugs" (Banks 36). Scientists believe that the cures for many more diseases will be discovered there in the future.

Degradation of the rainforests

Tropical and temperate rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century and the area covered by rainforests around the world is rapidly shrinking. It is estimated that the rainforest was reduced by about 58,000 km² annually in the 1990s. Rainforests used to cover 14% of the Earth's surface. This percentage is now down to 6% and it is estimated by some that the remaining natural rainforests could disappear within 40 years (mid-21st century). Biologists have estimated that large numbers of species are being driven to extinction, possibly more than 50,000 a year, due to the removal of habitat with destruction of the rain forests. Protection and regeneration of the rainforests is a key goal of many environmental charities and organisations, including [http://www.ecologyfund.com/ EcologyFund] and the Nature Conservancy.

Bibliography

- Richards, P. W. (1996). The tropical rainforest. 2nd ed. Cambridge University Press ISBN 0521421942
- Whitmore, T. C. (1998) An introduction to tropical rain forests. 2nd ed. Oxford University Press. ISBN 0198501471

External links

- [http://forests.org/ Forest Conservation Portal]
- [http://www.rainforestlive.org.uk/ Rainforest Live - Facts & Figures]
- [http://www.savetherainforest.org/index.htm Save The Rainforest]
- [http://nature.org/rainforests/explore/facts.html Rainforest facts and information] from The Nature Conservancy
- [http://www.rainforest-alliance.org/resources/forest-facts/ Rainforest Alliance]
- [http://rite.ed.qut.edu.au/old_oz-teachernet/projects/virtual-field-trips/rainforests/topics.html Virtual Rainforest Trip]
- [http://www.cfact.org/site/print.asp?idarticle=214 CFACT.org (a free-market group that disputes some claims)]
- [http://www.pygmies.info/ Rainforest people - Pygmies] Culture of the African rainforest people, with photos of nature and animals
- [http://www.amazonteam.org/index.html Amazon Conservation Team] An organization working in partnership with indigenous people in conserving biodiversity, health, and culture in tropical America. Category:Terrestrial biomes ja:%E7%86%B1%E5%B8%AF%E9%9B%A8%E6%9E%97 zh-min-nan:Ú-lîm

Temperate coniferous forests

Temperate coniferous forests are a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest. In most temperate coniferous forests, evergreen conifers predominate, while some are a mix of conifers and broadleaf evergreen trees and/or broadleaf deciduous trees. Temperate evergreen forests are common in the coastal areas of regions that have mild winters and heavy rainfall, or inland in drier climates or mountain areas. Many species of trees inhabit these forests including cedar, cypress, douglas-fir, fir, juniper, kauri, pine, podocarpus, spruce, redwood and yew. The understory also contains a wide variety of herbaceous and shrub species. Structurally, these forests are rather simple, generally consisting of two layers: an overstory and understory. Some forests may support an intermediate layer of shrubs. Pine forests support an herbaceous understory that is generally dominated by grasses and herbaceous perennials, and are often subject to ecologically important wildfires. Temperate rain forests only occur in seven regions around the world: the Pacific temperate rain forests of the Pacific Northwest, the Valdivian temperate rain forests of southwestern South America, the rain forests of New Zealand and Tasmania, northwest Europe (small pockets in Ireland, Scotland, Iceland and a somewhat larger area in Norway), southern Japan, and the eastern Black Sea-Caspian Sea region of Turkey and Georgia to northern Iran. The moist conditions of temperate rain forests generally support an understory of mosses, ferns and some shrubs. Temperate rain forests can be Temperate coniferous forests or Temperate broadleaf and mixed forests. The temperate coniferous rain forests sustain the highest levels of biomass in any terrestrial ecosystem and are notable for trees of massive proportions, including Giant Sequoia (Sequoiadendron gigantea), Coast Redwood (Sequoia sempervirens), Douglas-fir (Pseudotsuga menziesii), Sitka Spruce (Picea sitchensis), Alerce (Fitzroya cupressoides) and Kauri (Agathis australis). These forests are quite rare, occurring in small areas of Western North America, southwestern South America and northern New Zealand. The Klamath-Siskiyou forests of northwestern California and southwestern Oregon is known for its rich variety of plant and animal species, including many endemic species.

Temperate coniferous forest ecoregions

Australasia ecozone
Australasian mixed temperate rain forests (New Zealand, Tasmania, southeast Australia)

Nearctic ecozone
Alberta Mountain forests (Canada) Alberta-British Columbia foothills forests (Canada) Arizona Mountains forests (United States) Atlantic coastal pine barrens (United States) Blue Mountains forests (United States) British Columbia mainland coastal forests (Canada, United States) Cascade Mountains leeward forests (Canada, United States) Central and Southern Cascades forests (United States) Central British Columbia Mountain forests (Canada) Central Mexican Volcanoes forests (Mexico) Central Pacific coastal forests (Canada, United States) Colorado Rockies forests (United States) Eastern Cascades forests (Canada, United States) Fraser Plateau and Basin complex (Canada) Great Basin montane forests (United States) Klamath-Siskiyou forests (United States) Middle Atlantic coastal forests (United States) North Central Rockies forests (Canada, United States) Northern California coastal forests (United States) Northern Pacific coastal forests (Canada, United States) Northern transitional alpine forests (Canada) Okanogan dry forests (Canada, United States) Piney Woods forests (United States) Puget lowland forests (Canada, United States) Queen Charlotte Islands (Canada) Sierra Juarez and San Pedro Martir pine-oak forests (Baja California, Mexico) Sierra Madre Occidental forests (Mexico; southeast Arizona, US) Sierra Madre Oriental forests (Mexico) Sierra Nevada forests (United States) South Central Rockies forests (United States) Southeastern conifer forests (United States) Wasatch and Uinta montane forests (United States)

Neotropic ecozone
Valdivian temperate rain forests (Argentina, Chile)

Palearctic ecozone
Alps conifer and mixed forests (France, Italy, Slovenia, Switzerland) Altai montane forest and forest steppe (China, Kazakhstan, Mongolia, Russia) Balkan montane conifer forests (Bosnia and Herzegovina, Bulgaria, Greece, Macedonia, Romania, Serbia and Montenegro) Caledonian conifer forests (United Kingdom) Carpathian montane conifer forests (Czech Republic, Poland, Romania, Slovakia, Ukraine) Da Hinggan-Dzhagdy Mountains conifer forests (China, Russia) East Afghan montane conifer forests (Afghanistan, Pakistan) Elburz Range forest steppe (Iran) Helanshan montane conifer forests (China) Hengduan Mountains subalpine conifer forests (China) Hokkaido montane conifer forests (Japan) Honshu alpine conifer forests (Japan) Khangai Mountains conifer forests (Mongolia, Russia) Mediterranean conifer and mixed forests (Algeria, Morocco, Tunisia) Northeastern Himalayan subalpine conifer forests (China, India, Bhutan) Northern Anatolian conifer and deciduous forests (Armenia, Georgia, Turkey) Nujiang Langcang Gorge alpine conifer and mixed forests (China) Qilian Mountains conifer forests (China) Qionglai-Minshan conifer forests (China) Sayan montane conifer forests (Mongolia, Russia) Scandinavian coastal conifer forests (Norway) Tian Shan montane conifer forests (China, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan)

Ecoregions

An ecoregion is "a relatively large area of land or water that contains a geographically distinct assemblage of natural communities." This description is part of a definition, by World Wildlife Fund that is widely accepted and used. However, the use of the term "relatively large" is interpreted differently in different locales. Another way of looking at an ecoregion is a "recurring pattern of ecosystems associated with characteristic combinations of soil and landform that characterise that region" (Brunckhorst, 2000). Others have defined ecoregions as areas of ecological potential based on combinations of biophysical parameters such as climate and topography. Biodiversity is also an important aspect of the study of ecoregions. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tend to be distinct from that of other ecoregions. World Wilfdlife Fund's full definition of an ecoregion is the following: :A large area of land or water that contains a geographically distinct assemblage of natural communities that ::(a) share a large majority of their species and ecological dynamics; ::(b) share similar environmental conditions, and; ::(c) interact ecologically in ways that are critical for their long-term persistence. :::--[http://www.worldwildlife.org/science/ecoregions.cfm World Wildlife Fund - Ecoregions] World Wildlife Fund ecologists currently divide the land surface of the Earth into 8 major ecozones containing 867 smaller terrestrial ecoregions (see list). Many consider this classification to be quite decisive, and some propose these as stable borders for bioregional democracy initiatives. The ecozones are very well-defined, following major continental boundaries, while the ecoregions are subject to more change and controversy. The use of the term ecoregion is an outgrowth of a surge of interest in ecosystems and their functioning. In particular, there is awareness of issues relating to spatial scale in the study and management of landscapes. It is widely recognized that interlinked ecosystems combine to form a whole that is "greater than the sum of its parts." There are many attempts to respond to ecosystems in an integrated way to achieve "multi-functional" landscapes and various interest groups from agricultural researchers to conservationists are using the ecoregion as a unit of analysis.
See also

- Biome
- Ecozone
- Ecotope
- Fresh water ecoregion
- Global 200
- Habitat
- Marine ecoregion
- Terrestrial ecoregion
Sources

- Brunckhorst, D. 2000. Bioregional planning: resource management beyond the new millennium. Harwood Academic Publishers: Sydney, Australia.
External links

- [http://www.worldwildlife.org/ecoregions/ World Wildlife Fund: ecoregions ]
- [http://www.sierraclub.org/ecoregions/ Sierra club: ecoregions]
- [http://www.planetdrum.org Activist network cultivating Ecoregions/Bioregions]
- [http://sis.agr.gc.ca/cansis/nsdb/ecostrat/intro.html A National Ecological Framework for Canada]
- [http://www.epa.gov/wed/pages/ecoregions/na_eco.htm#Level%20I Ecoregions of North America] Category:Ecology Category:Ecoregions Category:Biogeography

Sequoia

:For other uses, see Sequoia (disambiguation).
Sequoia is a genus in the cypress family Cupressaceae, containing the single species Sequoia sempervirens. Common names include Coast Redwood and California Redwood (it is one of three species of trees known as redwoods). It is an evergreen, long-lived, monoecious tree living for up to 2,000 years, and is the tallest tree in the world, reaching up to 112 m in height, and 7 m diameter at the base. It is probably named after the Cherokee Indian leader, Sequoyah, though this is uncertain. The name Sequoia is also used as a general term for the subfamily Sequoioideae in which this genus is classified together with Sequoiadendron (Giant Sequoia) and Metasequoia (Dawn Redwood). Metasequoia The crown is conical, with horizontal to slightly drooping branches. The bark is very thick, up to 30 cm thick and quite soft, fibrous and a bright red-brown when freshly exposed (whence the name 'redwood'), weathering darker. The root system is composed of deep, wide-spreading lateral roots. The leaves are variable, being 15-25 mm long and flat on young trees and shaded shoots in the lower crown of old trees, and scale-like, 5-10 mm long on shoots in full sun in the upper crown of older trees; there is a full range of transition between the two extremes. They are dark green above, and with two blue-white stomatal bands below. Leaf arrangement is spiral, but the larger shade leaves are twisted at the base to lie in a flat plane for maximum light capture. The cones are ovoid, 15-32 mm long, with 15-25 spirally arranged scales; pollination is in late winter with maturation about 8-9 months after. Each cone scale bears 3-7 seeds, each seed 3-4 mm long and 0.5 mm broad, with two wings 1 mm wide. The seeds are released when the cone scales dry out and open at maturity. Its genetic makeup is unusual among conifers, being a hexaploid (6n) and likely autoallopolyploid (AAAABB). The mitochondrial genome is (unlike other conifers) paternally inherited (Neale et al. 1989).

Statistics

Trees over 60 m (200 feet) are common, and many are over 90 m (300 feet).
- The tallest is the "Stratosphere Giant" in the Humboldt Redwoods State Park, at 112.83 metres, last measured in 2004 (was 112.34 m in Aug 2000 and 112.56 m in 2002).
- There are 15 known living trees more than 110 m (361 feet) tall.
- There are 47 trees that are more than 105 m (344.5 feet) tall.
- A tree claimed to be 115.8 m (380 feet) was cut down in 1912.
- The tallest non-redwood tree is a 100.3 m (329 foot) tall Douglas-fir. In 2004, an article in Nature reported that the theoretical maximum potential height of Coast Redwoods (or any other tree) is limited to between 122-130 m (400-425 feet), due to gravity and the friction between water and the vessels through which it flows. The largest in volume is the "Del Norte Titan", with an estimated volume of 1044.7 m³; it is 93.57 m tall with a diameter of 7.22 m. Among current living trees only 15 Giant Sequoias are larger than this; these are shorter, but have thicker trunks, giving the largest Giant Sequoia a volume of 1,487 cubic metres (52,510 cubic feet). A redwood cut down in 1926 had a claimed volume of 1,794 cubic metres (63,350 cubic feet), but this is not verified.

Reproduction

Giant Sequoia Giant Sequoia Giant Sequoia Coast Redwood reproduces both sexually and asexually. Seed production begins at 10-15 years of age, and large seed crops occur frequently, but viability of the seed is low, typically below 20%. The low viability may be an adaptation to discourage seed predators, which do not want to waste time sorting chaff (empty seeds) from edible seeds. The winged seeds are small and light, weighing 3.3-5 mg (200-300 seeds/g; 5600-8500/ounce). The wings are not effective for wide dispersal, and seeds are dispersed by wind an average of only 60-120 m (200-400 feet) from the parent tree. Coast Redwoods can reproduce asexually by layering or sprouting from the root crown, stump, or even fallen branches. Sprouts originate from dormant or adventitious buds at or under the surface of the bark. The dormant sprouts are stimulated when the adult redwood gets damaged or starts to die. Many sprouts spontaneously erupt and develop round the circumference of the tree trunk. Within a short period after sprouting each sprout will develop its own root system, with the dominant sprouts forming a ring of trees around the parent root crown or stump. This ring of trees is called a "fairy ring". Sprouts can achieve heights of 2.3 m (8 feet) in a single growing season. They are able to reproduce using burls. A burl is a type of tumor that commonly appears on a redwood tree below the soil line. It rarely appears above the soil line, especially above 3m. Shoot clones commonly sprout from burls and are often turned into decorative hedges when found in suburbia. There have been some reported cases when a burl was made into furniture and began sprouting.

Range and ecology

Coast Redwoods occupy a narrow strip of land approximately 750 km (470 miles) in length and 8-75 km (5-47 miles) in width along the Pacific coast. The northern boundary of its range is marked by two groves on the Chetco River on the western fringe of the Klamath Mountains, 25 km (15 miles) north of the California-Oregon border. The largest populations are in Jedediah Smith Redwoods State Park (Del Norte County), Redwood National Park and Humboldt Redwoods State Park (Humboldt County). The furthest inland are 75 km from the sea, in Napa County. The southern boundary of the range is marked by a grove in Salmon Creek Canyon in the Santa Lucia Mountains of southern Monterey County. This native area provides a unique environment with heavy seasonal rains (2500 mm or 100 in annually), cool coastal air and fog keeping this forest constantly damp year round. As this heavy rain has left the soil with few nutrients, these trees depend on the entire biotic community of the forest, and complete recycling of the trees when dead. Logging interrupts this process. This forest community includes Douglas-fir, Western Hemlock, Tanoak, Madrone, and other trees along with a wide variety of ferns, Redwood sorrel, mosses and mushrooms. Redwood forests provide habitat for a variety of mammals, birds, reptiles, and amphibians. Remnant old growth redwood stands provide habitat for the federally threatened Spotted Owl and the California-endangered Marbled Murrelet. The thick, tannin-rich bark, combined with foliage that starts high above the ground provides good protection from both fire and insect damage, contributing to the Coast Redwood's longevity. The oldest known Coast Redwood is about 2200 years old; many others in the wild exceed 600 years.

Cultivation and uses

Coast Redwood is one of California's most valuable timber species. The second growth wood is soft, weak, easily split, and resistant to decay. The clear wood is used for dimension stock, siding, fencing, and shingles. Redwood burls are used in the production of table tops, veneers, and turned goods. The phenolics and tannins present in old growth redwood stock affords excellent termite and water damage protection. Old growth redwood construction is highly prized as a result. Only 3% of the present redwood forest is old growth, and is protected from further exploitation. More and more of the second growth forest is being converted into protected areas with hopes of them taking on old growth forest characteristics. Examples of this are the Big Basin State Park and the recently acquired San Lorenzo River Redwoods. Some of the remaining forest consists of redwood plantations grown on a short (40-70 years) rotation. Other areas are slowly succumbing to suburban sprawl. The Coast Redwood is also naturalised in New Zealand.

References and external links

- [http://www.conifers.org/cu/se/index.htm Gymnosperm Database - Sequoia sempervirens]
- [http://www.nps.gov/redw/trees.html US National Park Service]
- [http://www.fs.fed.us/database/feis/plants/tree/seqsem/index.html US Forest Service Fire Effects Database]
- Reed F. Noss (editor), The Redwood Forest: history, ecology and conservation of the Coast Redwood (ISBN 1-55963-726-9)
- Neale, D. B., Marshall, K. A., & Sederoff, R. R. (1989). Chloroplast and Mitochondrial DNA are Paternally Inherited in Sequoia sempervirens (D.Don) Endl. Proc. Natl. Acad. Sci. USA 86 (23): 9347-9349. Available [http://www.pnas.org/cgi/reprint/86/23/9347 online] Category:Cupressaceae ja:セコイア

Giant Sequoia

The Giant Sequoia or Sierra Redwood (Sequoiadendron giganteum) is one of a number of species of coniferous trees known as redwoods, classified in the family Cupressaceae in the subfamily Sequoioideae together with Coast Redwood and Dawn Redwood.

Description

Giant Sequoia is the world's largest tree in terms of total volume. They grow to an average height of 70-85 m (230-280 ft) and 5-7 m (16-23 ft) in diameter. Record trees have been reported to be 93.6 m (307 ft) in height and 8.85 m (29 ft) in diameter. The oldest known Giant Sequoia based on ring count is 3,200 years old. Sequoia bark is fibrous, furrowed, and may be 60 cm (2 ft) thick at the base of the columnar trunk. It provides significant fire protection for the trees. The leaves are evergreen, awl-shaped, 3-6 mm long, and arranged spirally on the shoots. The seed cones are 4-7 cm long and mature in 18-20 months, though they typically remain green and closed for up to 20 years; each cone has 30-50 spirally arranged scales, with several seeds on each scale giving an average of 230 seeds per cone. The seed is dark brown, 4-5 mm long and 1 mm broad, with a 1 mm wide yellow-brown wing along each side. Some seed is shed when the cone scales shrink during hot weather in late summer, but most seeds are liberated when the cone dries out from fire heat and/or insect damage (see Ecology, below). seed ]] Giant Sequoia regenerates primarily by seed, although occasionally it may reproduce naturally by vegetative methods; trees up to about 20 years old may produce stump sprouts subsequent to injury. Giant Sequoia of all ages may sprout from the bole when old branches are lost to fire or breakage, but (unlike Coast Redwood) mature trees do not sprout from cut stumps. Young trees start to bear cones at the age of 20 years. At any given time, a large tree may be expected to have approximately 11,000 cones. The upper part of the crown of any mature Giant Sequoia invariably produces a greater abundance of cones than its lower portions. A mature Giant Sequoia has been estimated to disperse from 300,000-400,000 seeds per year. The winged seeds may be carried up to 180m (600 ft) from the parent tree. Lower branches die fairly readily from shading, but trees less than 100 years old retain most of their dead branches. Trunks of mature trees in groves are generally free of branches to a height of 20-50 m, but solitary trees will retain low branches.

Distribution

Giant Sequoia is usually found in a humid climate characterized by dry summers and snowy winters. Most Giant Sequoia groves are on granitic-based residual and alluvial soils. The elevation of the Giant Sequoia groves generally ranges from 1,400-2,000m (4,600-6,600 ft) in the north, and 1,700-2,150 m (5,600-7,000 ft) to the south. Giant Sequoia generally appears on southern slopes in its northern distribution and on more northerly slopes in the south. snow) most popular attractions.]] The natural distribution of Giant Sequoia is restricted to along a limited area of the western Sierra Nevada, California. It occurs in scattered groves, with a total of 65-76 groves (see list of sequoia groves for a full inventory), comprising a total area of only 14,416 ha (144.16 km² / 35,607 acres). Nowhere does it grow in pure stands, although in a few small areas stands do approach a pure condition. The northern two-thirds of its range, from the American River in Placer County southward to the Kings River, has only eight disjunct groves. The remaining southern groves are concentrated between the Kings River and the Deer Creek Grove in southern Tulare County. Groves range in size from 1,240ha (3,100 acres) with 20,000 mature trees, to small groves with only six living trees. Many are protected in Sequoia and Kings Canyon National Parks and Giant Sequoia National Monument. High levels of reproduction are not necessary to maintain the present population levels. Few groves, however, have sufficient young trees to maintain the present density of mature Giant Sequoias for the future. The majority of Giant Sequoias are currently undergoing a gradual decline in density since the European settlement days.

Ecology

The Giant Sequoias are having difficulty reproducing in their original habitat (and very rarely reproduce in cultivation) due to the seeds only being able to grow successfully in mineral soils in full sunlight, free from competing vegetation. Although the seeds can germinate in moist needle humus in the spring, these seedlings will die as the duff dries in the summer. They therefore require periodic wildfire to clear competing vegetation and soil humus before successful regeneration can occur. Without fire, shade-loving species will crowd out young sequoia seedlings, and sequoia seeds will not germinate. When full grown, these trees typically require large amounts of water and are therefore often concentrated near streams. Fires also bring hot air high into the canopy via convection, which in turn dries and opens the cones. The subsequent release of large quantities of seeds coincides with the optimal post-fire seedbed conditions. Loose ground ash may also act as a cover to protect the fallen seeds from ultraviolet radiation damage. Due to fire suppression efforts and livestock grazing during the early and mid 20th century, low-intensity fires no longer occurred naturally in many groves, and still do not occur in some groves today. The suppression of fires also led to ground fuel build-up and the dense growth of fire-sensitive White Fir. This increased the risk of more intense fires that can use the firs as ladders to threaten mature Giant Sequoia crowns. Natural fires may also be important in keeping carpenter ants in check. In 1970 the National Park Service began controlled burns of its groves to correct these problems. Current policies also allow natural fires to burn. One of these untamed burns severely damaged the second-largest tree in the world, the Washington tree, in September 2003, 45 days after the fire started. This damage made it unable to withstand the snowstorm of January 2005, leading to the collapse of over half the trunk. In addition to fire, there are also two animal agents for Giant Sequoia seed release. The more significant of the two is a longhorn beetle (Phymatodes nitidus) that lays eggs on the cones, into which the larvae then bore holes. This cuts the vascular water supply to the cone scales, allowing the cones to dry and open for the seeds to fall. Cones damaged by the beetles during the summer will slowly open over the next several months. Some research indicates that many cones, particularly higher in the crowns, may need to be partially dried by beetle damage before fire can fully open them. The other agent is the Douglas Squirrel (Tamiasciurus douglasi) that gnaws on the fleshy green scales of younger cones. The squirrels are active year round, and some seeds are dislodged and dropped as the cone is eaten.

Discovery and naming

Douglas Squirrel The Giant Sequoia was well known to Native American tribes living in its area. Native American names for the species include Wawona, Toos-pung-ish and Hea-mi-withic, the latter two in the language of the Tule River Tribe. The first reference to the Giant Sequoia by Europeans is in 1833, in the diary of the explorer J. K. Leonard; the reference does not mention any locality, but his route would have taken him through the Calaveras Grove. This discovery was not publicised. The next European to see the species was John M. Wooster, who carved his initials in the bark of the 'Hercules' tree in the Calaveras Grove in 1850; again, this received no publicity. Much more publicity was given to the "discovery" by Augustus T. Dowd of the Calaveras Grove in 1852, and this is commonly, if incorrectly, cited as the species' discovery. The tree found by Dowd, christened the 'Discovery Tree', was felled in 1853. The first scientific naming of the species was by John Lindley in 1853, who named it Wellingtonia gigantea, without realising this was an invalid name under the botanical code as the name Wellingtonia had already been used earlier for another unrelated plant (Wellingtonia arnottiana in the family Sabiaceae). The following year, Joseph Decaisne transferred it to the same genus as the Coast Redwood, naming it Sequoia gigantea, but again this name was invalid, having been applied earlier (in 1847, by Endlicher) to the Coast Redwood. The name Washingtonia californica was also applied to it by Winslow in 1854, though this too is invalid, belonging to the palm genus Washingtonia. In 1907 it was placed by Carl Ernst Otto Kuntze in the otherwise fossil genus Steinhauera, but doubt as to whether the Giant Sequoia is related to the fossil originally so named makes this name invalid. The nomenclatural oversights were finally corrected in 1939 by J. Buchholz, who also pointed out that the Giant Sequoia is distinct from the Coast Redwood at the genus level and coined the name Sequoiadendron giganteum for it. Other English vernacular names include Sierra Redwood, Giant Redwood, or simply Big Tree.

List of the ten largest Giant Sequoias

As of February 2005, the ten largest trees by volume are: Source: United States National Park Service - [http://www.nps.gov/seki/bigtrees.htm]. Note that the volume figures have a low degree of accuracy, due to difficulties in measurement; stem diameter measurements are taken at a few set heights up the trunk, and assume that the trunk is circular in cross-section, and that taper between measurement points is even. The volume measurements also do not take cavities into account. The measurements are however trunk-only, and do not include the volume of wood in the branches or roots.

Uses

National Park Service] Wood from mature Giant Sequoias is highly resistant to decay, but is fibrous and brittle, making it generally unsuitable for construction. From the 1880s through the 1920s logging took place in many groves in spite of marginal commercial returns. Due to their weight and brittleness trees would often shatter when they hit the ground, wasting much of the wood. Loggers attempted to cushion the impact by digging trenches and filling them with branches. Still, it is estimated that as little as 50 percent of the timber made it from groves to the mill. The wood was used mainly for shingles and fence posts, or even for matchsticks. Pictures of the once majestic trees broken and abandoned in formerly pristine groves, and the thought of the giants put to such modest use, spurred the public outcry that caused most of the groves to be preserved as protected land. The public can visit an example of 1880s clear-cutting at Big Stump Grove near Grant Grove. As late as the 1980s some immature trees were logged in Sequoia National Forest, publicity of which helped lead to the creation of Giant Sequoia National Monument. The wood from immature trees is less brittle, with recent tests on young plantation-grown trees showing it similar to Coast Redwood wood in quality. This is resulting in some interest in cultivating Giant Sequoia as a very high-yielding timber crop tree, both in California and also in parts of western Europe, where it may grow more efficiently than Redwoods. In the northwest United States some entrepreneurs have also begun growing Giant Sequoias for Christmas trees. Besides these attempts at tree farming, the principle economic uses for Giant Sequoia today are tourism and horticulture (see Cultivation, below).

Giant Sequoia in cultivation

horticulture] Giant Sequoia is a popular ornamental tree in many areas. It was first brought into cultivation in 1853 by Scotsman John D. Matthew, who collected a small quantity in the Calaveras Grove, arriving with it in Scotland in August 1853 (Mitchell 1996). A much larger shipment of seed collected (also in the Calaveras Grove) by William Lobb, acting for the Veitch Nursery, arrived in England in December 1853. Growth in Britain is very fast, with the tallest tree, at Benmore in southwest Scotland, reaching 54 m at age 150 years ([http://www.tree-register.org/ Tree Register of the British Isles]), and several others from 50-53 m tall; the stoutest is 3.55 m diameter, in Perthshire. Other areas where it is successfully grown include most of western and southern Europe, the Pacific Northwest of North America north to at least Vancouver, southeast Australia, New Zealand and central-southern Chile. Growth rates in some areas are remarkable; one young tree in Italy reached 22 m tall and 88 cm trunk diameter in 17 years. In the northeastern USA there has been some limited success in growing the species, but growth is much slower there, and it is prone to Cercospora and Kabatina fungal diseases due to the humid summer climate there. The tallest reported in the east is one about 35 m tall, at Blithewold Gardens, in Bristol, Rhode Island. A recently selected cold tolerant cultivar 'Hazel Smith' is proving more successful in that area. This clone was the sole survivor of several hundred seedlings grown at a nursery in New Jersey.

References

- Aune, P. S. (ed.) 1994. Proceedings of the Symposium on Giant Sequoias. US Dept. of Agriculture Forest Service (Pacific Southwest Research Station) General Technical Report PSW-GTR-151.
- Mitchell, A. F. 1996. Alan Mitchell's Trees of Britain. HarperCollins ISBN 0-00-219972-6.
- Thomas, H. H., Shellhammer, H. S., and Stecker, R. E. 1980. Giant sequoia ecology. U.S. Department of the Interior, National Park Service, Scientific Monograph Series 12. Washington, DC. 182 p.
- Kilgore, B. 1970. Restoring Fire to the Sequoias. National Parks and Conservation Magazine 44 (277): 16-22.

External links

- [http://www.conifers.org/cu/se2/index.htm Gymnosperm Database - Sequoiadendron giganteum]
- [http://www.pinetum.org/cones/Sequoiadendron.htm Arboretum de Villardebelle - photos of cones & shoots with phenology notes]
- [http://www.fs.fed.us/database/feis/plants/tree/seqgig/ Forest Service database entry on Sequoiadendron giganteum]
- [http://www.nps.gov/seki/fire/pdf/ts_yc90.pdf Giant Sequoia Fire History in Mariposa Grove, Yosemite National Park (.pdf file!)] Category:Cupressaceae Category:Sierra Nevada

Coast Douglas-fir

The Coast Douglas-fir (Pseudotsuga menziesii subsp. menziesii) is an evergreen conifer native to the coastal regions of western North America, from west-central British Columbia, Canada southward to central California, United States. In Oregon and Washington its range is continuous from the Cascades crest west to the Pacific Ocean. In California, it is found in the Klamath and Coast Ranges as far south as the Santa Cruz Mountains, and in the Sierra Nevada as far south as the Yosemite region. It occurs from near sea level along the coast to 1,800 m in the Sierra Nevada. Further inland, Coast Douglas-fir is replaced by the related Rocky Mountain Douglas-fir (Pseudotsuga menziesii subsp. glauca). Coast Douglas-fir is a very large tree, the second-tallest in the world (after Coast Redwood). Trees 60-75 m (200-250 feet) or more in height and 1.5-2 m (5-6 feet) in diameter are common in old growth stands. The tallest specimen is the "Brummit Fir", 100.3 m tall, at East Fork Brummit Creek in Coos County, Oregon, the stoutest is the "Queets Fir", 4.85 m diameter, in the Queets River valley, Olympic National Park, Washington. It commonly lives more than 500 years and occasionally more than 1,000 years. The bark on young trees is thin, smooth, gray, and contains numerous resin blisters. On mature trees, it is 10-30 cm thick (4-12 inches) and corky. The shoots are brown to olive-green, turning gray-brown with age, smooth, though not as smooth as fir shoots, and finely pubescent with short dark hairs. The buds are a very distinctive narrow conic shape, 4-8 mm long, with red-brown bud scales. The leaves are spirally arranged but slightly twisted at the base to lie in flattish either side of the shoot, needle-like, 2-3.5 cm long, green above with no stomata, and with two whitish stomatal bands below. Unlike the Rocky Mountain Douglas-fir, Coast Douglas-fir foliage has a noticeable sweet fruity-resinous scent, particularly if crushed. stomata] The mature female seed cones are pendent, 5-11 cm (2-4 inches) long, 2-3 cm broad when closed, opening to 4 cm broad. They are produced in spring, green at first, maturing orange-brown in the autumn 6-7 months later. The seeds are 5-6 mm long and 3-4 mm broad, with a 12-15 mm wing. The male (pollen) cones are 2-3 cm long, dispersing yellow pollen in spring. In forest conditions, old individuals typically have a narrow, cylindric crown beginning 20-40 m (65-130 feet) above a branch-free trunk. Self-pruning is generally slow and trees retain their lower limbs for a long period. Young, open-grown trees typically have branches down to near ground level. It often takes 70-80 years for the trunk to be clear to a height of 5 m (17 feet) and 100 years to be clear to a height of 10 m (33 feet). Appreciable seed production begins at 20-30 years in open-grown Coast Douglas-fir. Seed production is irregular; over a 5-7 year period, stands usually produce one heavy crop, a few light or medium crops, and one crop failure. Even during heavy seed crop years, only about 25 percent of trees in closed stands produce an appreciable number of cones. Each cone contains around 25 to 50 seeds. Seed size varies; average number of cleaned seeds varies from 70-88/g (32,000-40,000 per pound). Seeds from the northern portion of Coast Douglas-fir's range tend to be larger than seed from the south.

Ecology

Coast Douglas-fir is the dominant tree in the Pacific Northwest, occurring in nearly all forest types, competes well on most parent materials, aspects, and slopes. Adapted to a moist, mild climate, it grows larger and faster than Rocky Mountain Douglas-fir. Associated trees include Sitka Spruce, Sugar Pine, Western White Pine, Ponderosa Pine, Grand Fir, Coast Redwood, Western Redcedar, California Incense-cedar, Lawson's Cypress, Tanoak, Bigleaf Maple and several others. Pure stands are also common, particularly north of the Umpqua River in Oregon. Shrub associates in the central and northern part of Coast Douglas-fir's range include Vine Maple (Acer circinatum), Salal (Gaultheria shallon), Pacific Rhododendron (Rhododendron macrophyllum), Oregon-grape (Mahonia aquifolium), Red Huckleberry (Vaccinium parvifolium), and Salmonberry (Rubus spectabilis). In the drier, southern portion of its range shrub associates include California Hazel (Corylus cornuta var. californica), Oceanspray (Holodiscus discolor), Creeping Snowberry (Symphoricarpos mollis), Western Poison-oak (Toxicodendron diversilobum), Ceanothus (Ceanothus spp.), and Manzanita (Arctospaphylos spp.). In wet coastal forests, nearly every surface of old-growth Coast Douglas-fir is covered by epiphytic mosses and lichens. Its rooting habit is not particularly deep, the roots tending to be shallower than those of same aged Ponderosa Pine, Sugar Pine, or California Incense-cedar, though deeper than Sitka Spruce. Some roots are commonly found in organic soil layers or near the mineral soil surface. Coast Douglas-fir seedlings are not a preferred browse of Black-tailed Deer and Wapiti, but can be an important food source for these animals during the winter when other preferred forages are lacking. Douglas-fir seeds are an extremely important food for small mammals. Mice, voles, shrews, and chipmunks consumed an estimated 65 percent of a Douglas-fir seed crop following dispersal in western Oregon. The seeds are also important in the diets of the Pine Siskin, Song Sparrow, Golden-crowned Sparrow, White-crowned Sparrow, Red Crossbill, Dark-eyed Junco, and Purple Finch. The Douglas squirrel harvests and caches great quantities of Douglas-fir cones for later use. They also eat mature pollen cones, developing inner bark, terminal shoots, and tender young needles. Mature or "old-growth" Coast Douglas-fir is the primary habitat of the Red tree vole and the Spotted Owl. Home range requirements for breeding pairs of spotted owls are at least 400 ha (4 km² / 1,000 acres) of old-growth. Red tree voles may also be found in immature forests if Douglas-fir is a significant component. This animal nests almost exclusively in the foliage of Douglas-fir trees. Nests are located 2-50 m (6-160 feet) above the ground. The red vole's diet consists chiefly of Coast Douglas-fir needles. In many areas Coast Douglas-fir needles are a staple in the spring diet of Blue Grouse. In the winter, porcupines primarily eat the inner bark of young conifers, especially Douglas-fir. Douglas-fir snags are abundant in forests older than 100-150 years and provide cavity-nesting habitat for numerous forest birds. The leaves are also used by the adelgid Adelges cooleyi; this 0.5 mm long sap-sucking insect is conspicuous on the undersides of the leaves by the small white "fluff spots" of protective wax that it produces. It is often present in large numbers, and can cause the foliage to turn yellowish from the damage in causes. Exceptionally, trees may be partially defoliated by it, but the damage is rarely this severe.

Forest Succession

The shade-intolerance of Douglas-fir plays a large role in the forest succession of lowland old growth communities of the Pacific Northwest. While mature stands of lowland old-growth forests contain many Western Hemlock (Tsuga heterophylla) seedlings, and some Western Redcedar (Thuja plicata) seedlings, Douglas-fir dominated stands contain almost no Douglas-fir seedlings. This seeming contradiction occurs because Douglas-firs are intolerant of shade and rarely survive for long within the shaded understory. When a tree dies in a mature forest the canopy opens up and sunlight becomes available as a source of energy for new growth. The shade-tolerant Western Hemlock seedlings that sprout beneath the canopy have a head-start on other seedlings. This competitive advantage allows the Western Hemlock to grow rapidly into the sunlight, while other seedlings still struggle to emerge from the soil. The boughs of the growing Western Hemlock limit the sunlight for smaller trees and severely limit the chances of shade-intolerant trees, such as the Douglas-fir. Over the course of centuries, Western Hemlock typically come to dominate the canopy of an old-growth lowland forest. However, Douglas-fir tolerates low-moisture conditions better than other climax trees of the area, such as the Western Hemlock and Western Redcedar. This quality often gives Douglas-firs a competitive advantage when the forest experiences a major disturbance. Periodically, portions of a Pacific Northwest lowland forest may be burned by wildfire, may be logged, or may be blown down by a wind-storm. These types of disturbances often create low-moisture conditions where Douglas-firs have an advantage over less drought-tolerant species. Conifers dominate the climax forests of the Coastal Douglas-fir. All of the climax conifers that grow alongside Douglas-fir can live for centuries, with a few species capable of living for over a millennium. Forests that exist on this time scale experiences the type of sporadic disturbances that allow mature stands of Douglas-firs to establish themselves as a persistent element within a mature old-growth forest. When old growth forests survive in a natural state, they often look like a patchwork quilt of different forest communities. Western Hemlock typically dominate old growth forests, but contain sections of Douglas-firs, Redcedar, Alder, and even Redwood forests on their southern extent, near the Oregon and California border. The logging practices of the last 200 years created artificial disturbances that caused Douglas-firs to thrive. The Douglas-fir's useful wood and its quick growth make it the crop of choice for many timber companies, which typically replant a clear-cut area with Douglas-fir saplings. The low-moisture conditions that exist within a clear-cut also naturally favor the regeneration of Douglas-fir. Because of clear-cut logging, almost all the Pacific Northwest forests not strictly set aside for protection are today dominated by Douglas-fir, while the normally dominant climax species, such as Western Hemlock and Western Redcedar are relatively rare.

Uses

Coast Douglas-fir is one of the worlds best timber producers and yields more timber than any other tree in North America. The wood is used for dimensional lumber, timbers, pilings, and plywood. Creosote treated pilings and decking are used in marine structures. The wood is also made into railroad ties, mine timbers, house logs, posts and poles, flooring, veneer, pulp, and furniture. Coast Douglas-fir is used extensively in landscaping. It is planted as a specimen tree or in mass screenings. It is also a popular Christmas tree.

External links

- [http://www.pinetum.org/cones/PScones.htm Arboretum de Villardebelle - cone photos]
- [http://www.conifers.org/pi/ps/menziesii2.htm Gymnosperm Database: Pseudotsuga menziesii subsp. menziesii]
- [http://www.fs.fed.us/database/feis/plants/tree/psemenm/index.html FEIS - Index of Species Information: Pseudotsuga menziesii var. menziesii] Douglas-fir, Coast

Alerce

Fitzroya is a genus in the cypress family Cupressaceae with only a single species, Fitzroya cupressoides native to the Andes mountains of central Chile and adjoining Argentina, where it is an important member of the Valdivian temperate rain forests. The scientific name of the genus honours Robert FitzRoy; common names include Lahuan (the Mapuche Native American name), Alerce (South American Spanish), and Patagonian Cypress. It is a very large evergreen tree, the largest tree species in South America, growing to 40-60 m tall and up to 5 m trunk diameter. The leaves are in decussate whorls of three, 3-6 mm long (to 8 mm long on seedlings) and 2 mm broad, marked with two white stomatal lines. The cones are globose, 6-8 mm diameter, opening flat to 12 mm across, with nine scales in three whorls of three. Only the central whorl of scales is fertile, bearing 2-3 seeds on each scale; the lower and upper whorls are small and sterile. The seeds are 2-3 mm long, flat, with a wing along each side. The seeds are mature 6-8 months after pollination. In 1993 a specimen from Chile was dated as 3622 years old. This gives it the second-greatest fully verified age recorded for any living tree (the oldest being the Great Basin Bristlecone Pine). Much larger specimens existed in the past before the species was heavily logged in the 19th and 20th centuries; Charles Darwin reported finding a specimen 12.6 m in diameter, which, if accurately measured, would have made it the stoutest tree ever measured anywhere in the world. A team of researchers from the University of Tasmania found fossilized foliage of Fitzroya on the Lea River of northwest Tasmania. The 35 million year-old fossil has been given the species name Fitzroya tasmanensis. The finding demonstrates the ancient floristic affinities between Australasia and southern South America, which botanists identify as the Antarctic flora.

Reference

Hill, R. S. and Whang, S. S. 1996. A new species of Fitzroya (Cupressaceae) from Oligocene sediments in north-western Tasmania. Australian Systematic Botany 9(6): 867-875.

External links

[http://www.conifers.org/cu/fi/ Gymnosperm Database - Fitzroya cupressoides] [http://www.chilebosque.cl/tree/fcupr.html Fitzroya cupressoides in Chilebosque] Category:Cupressaceae Category:Argentine flora Category:Flora of Chile

North America

North America is a continent in the northern hemisphere bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west by the North Pacific Ocean. It covers an area of 24,497,994 km² (9,458,728 sq mi), or about 4.8% of the Earth's surface. As of July 2002, its population was estimated at more than 514,600,000. It is the third largest continent in area, after Asia and Africa, and is fourth in population after Asia, Africa, and Europe. Both North and South America are named after Amerigo Vespucci, who was the first European to suggest that the Americas were not the East Indies, but a previously undiscovered (by Europeans) New World. North America occupies the northern portion of the landmass generally referred to as the New World, the Western Hemisphere, the Americas, or simply America. North America's only land connection is to South America at the narrow Isthmus of Panama. (For geopolitical reasons, all of Panama – including the segment east of the Panama Canal in the isthmus – is often considered a part of North America alone.) According to some authorities, North America begins not at the Isthmus of Panama but at the Isthmus of Tehuantepec, with the intervening region called Central America and resting on the Caribbean Plate. Most, however, tend to see Central America as a region of North America, considering it too small to be a continent on its own. Greenland, although a part of North America geographically, is not considered to be part of the continent politically.

Physical features

Greenland, plutonic, metamorphic rock types of North America. ]] Plate tectonics recognizes the vast majority of North America as being the surface of the North American Plate. Parts of California and western Mexico are known for being the edge of the Pacific Plate, with the two plates meeting along the San Andreas fault. The continent can be divided into four great regions (each of which contains many sub-regions): the Great Plains stretching from the Gulf of Mexico to the Canadian Arctic; the geologically young, mountainous west, including the Rocky Mountains, the Great Basin, California and Alaska; the raised but relatively flat plateau of the Canadian Shield in the northeast; and the varied eastern region, which includes the Appalachian Mountains, the coastal plain along the Atlantic seaboard, and the Florida peninsula. Mexico, with its long plateaus and cordilleras, falls largely in the western region, although the eastern coastal plain does extend south along the Gulf. The western mountains are split in the middle, into the main range of the Rockies and the coast ranges in California, Oregon, Washington, and British Columbia with the Great Basin – a lower area containing smaller ranges and low-lying deserts – in between. The highest peak is Denali in Alaska. Since 1931, Rugby, North Dakota, has officially been recognized as being at the geographic center of North America. The location is marked by a 4.5 metre (15 foot) field stone obelisk. Image:North america terrain 2003 map.jpg|North America bedrock and terrain. Image:North america basement rocks.png|North American cratons and basement rocks. Image:North America Tectonic Elements.jpg|Tectonic elements of North America Image:North america craton nps.gif|North American craton.

Territories and regions

craton On the main continent landmass, there are three large and relatively populous countries:
- Canada - many large islands off the shore of North America belong to Canada, including Vancouver Island and the Queen Charlotte Islands on the west, Prince Edward Island, Newfoundland and Cape Breton Island on the east, and the Canadian Arctic islands (including Ellesmere Island, Baffin Island, and Victoria Island) in the north
- Mexico - the Revillagigedo archipelago and numerous smaller islands off its coast belong to Mexico
- The United States - the 48 contiguous states and Alaska are part of North America, while the state of Hawaii in the Pacific Ocean is not; the Aleutian Islands south of Alaska also belong to the U.S. At the southern end of the continent, in a relatively small area known as Central America, are the countries of:
- Belize
- Costa Rica
- El Salvador
- Guatemala
- Honduras
- Nicaragua
- Panama ¹ At the southeastern end of the continent lies a chain of islands territories called the Antilles, the Caribbean or the West Indies, which include the countries:
- Antigua and Barbuda
- Bahamas
- Barbados
- Cuba
- Dominica
- Dominican Republic
- Grenada
- Haiti
- Jamaica
- Saint Kitts and Nevis
- Saint Lucia
- Saint Vincent and the Grenadines
- Trinidad and Tobago ¹ And the dependencies:
- Anguilla (British overseas territory)
- Aruba ² (part of the Kingdom of the Netherlands)
- Cayman Islands (British overseas territory)
- Guadeloupe (French région d'outre-mer)
- Martinique (French région d'outre-mer)
- Montserrat (British overseas territory)
- Navassa Island (U.S. territory)
- Netherlands Antilles ¹ (part of the Kingdom of the Netherlands)
- Puerto Rico (U.S. commonwealth)
- Turks and Caicos Islands (British overseas territory)
- British Virgin Islands (British overseas territory)
- U.S. Virgin Islands (territory of the USA) Lying in the Atlantic Ocean but considered part of the continent are the dependencies:
- Bermuda, a British overseas territory found about 1,072 km (670 mi.) southeast of New York City
- Greenland, the largest island in the world and a self-governing dependency of Denmark, which is located in the far north of the continent to the east of Nunavut.
- Saint Pierre and Miquelon, a French collectivité d'outre-mer off the south coast of