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Mixedwood Stand
{{context, date=December 2014 A mixedwood stand is a forest type in which 26% to 75% of the canopy is made up of softwood trees.Natural Resources Canada, Canadian Forest Service. 1995. Silviculture terms in Canada (Terminologie de la sylviculture au Canada). NRCan, CFS, Ottawa, Ontario, 2nd edition. 109 p. Uncertainties of the definition, extent, and potential of mixedwood types necessitate the placement of some mensurational bounds on the subject of mixedwood management, especially the distribution and component sub-types, age classes, advance growth, productivity, and rotation ages. A major ecological factor in mixedwood management is the spruce budworm; another is the problem of providing for sufficient white spruce regeneration.Project 07-24-0 analysis, Artificial regeneration of spruce in the spruce–fir forest type of Ontario. J.B. Scarratt, Canadian Forest Service, Ontario Region, Sault Ste Marie, Ontario. E3933 The white spruce–aspen mixedwood associations of the Prair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds ''in situ''. It does not include land that is predominantly under agricultural or urban use." Using this definition, '' Global Forest Resources Assessment 2020'' (FRA 2020) found that forests covered , or approximately 31 percent of the world's land area in 2020. Forests are the predominant terrestrial ecosystem of Earth, and are found around the globe. More than half of the world's forests are found in only five countries (Brazil, Canada, China, Russia, and the United States). The largest share of forests (45 percent) are in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canopy (biology)
In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms ( epiphytes, lianas, arboreal animals, etc.). The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Sometimes the term canopy is used to refer to the extent of the outer layer of leaves of an individual tree or group of trees. Shade trees normally have a dense canopy that blocks light from lower growing plants. Observation Early observations of canopies were made from the ground using binoculars or by examining fallen material. Researchers would sometimes erroneously rely on extrapolation by using more reachable samples taken from the understory. In some cases, they would use unconventional methods such as chairs susp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Softwood
file:Pinus sylvestris wood ray section 1 beentree.jpg, Scots Pine, a typical and well-known softwood Softwood is wood from gymnosperm trees such as conifers. The term is opposed to hardwood, which is the wood from angiosperm trees. The main differences between hardwoods and softwoods is that the structure of hardwoods lack resin canals, whereas softwoods lack pores (though not all softwoods have resin canals). Characteristics Softwood is wood from gymnosperm trees such as pines and spruces. Softwoods are not necessarily softer than hardwoods. In both groups there is an enormous variation in actual wood hardness, the range of density in hardwoods completely including that of softwoods. Some hardwoods (e.g. balsa) are softer than most softwoods, while the hardest hardwoods are much harder than any softwood. The woods of longleaf pine, Douglas fir, and Taxus, yew are much harder in the mechanical sense than several hardwoods. Softwoods are generally most used by the construction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spruce Budworm
''Choristoneura'' is a genus of moths in the family Tortricidae. Several species are serious pests of conifers, such as spruce and are known as spruce budworms. Species *''Choristoneura adumbratanus'' (Walsingham, 1900) *'' Choristoneura africana'' Razowski, 2002 *''Choristoneura albaniana'' (Walker, 1863) *'' Choristoneura argentifasciata'' Heppner, 1989 *'' Choristoneura biennis'' Freeman, 1967 *'' Choristoneura bracatana'' (Rebel, in Rebel & Rogenhofer, 1894) *''Choristoneura carnana'' (Barnes & Busck, 1920) *'' Choristoneura chapana'' Razowski, 2008 *'' Choristoneura colyma'' Razowski, 2006 *''Choristoneura conflictana'' (Walker, 1863) *'' Choristoneura diversana'' (Hubner, 814-1817 *''Choristoneura evanidana'' (Kennel, 1901) *'' Choristoneura expansiva'' X.P.Wang & G.J.Yang, 2008 *'' Choristoneura ferrugininotata'' Obraztsov, 1968 *''Choristoneura fractivittana'' (Clemens, 1865) *''Choristoneura freemani'' Razowski, 2008, western spruce budworm *''Choristoneura fumiferana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and tissue growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. Regeneration can either be complete where the new tissue is the same as the lost tissue, or incomplete where after the necrotic tissue comes fibrosis. At its most elementary level, regeneration is mediated by the molecular processes of gene regulation and involves the cellular processes of cell proliferation, morphogenesis and cell differentiation. Regeneration in biology, however, mainly refers to the morphogenic processes that characterize the phenotypic plasticity of traits allowing multi-cellular organisms to repair and maintain the integrity of their physiological and morphological states. Above the genetic level, regeneration is fundamentally regulated by asexual cellular processes. Regeneration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspen
Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') *''Populus davidiana'' – Korean aspen (Eastern Asia) *''Populus grandidentata'' – Bigtooth aspen (eastern North America, south of ''P. tremuloides'') *''Populus sieboldii'' – Japanese aspen (Japan) *''Populus tremula'' – Eurasian aspen (northern Europe and Asia) *''Populus tremuloides'' – Quaking aspen or trembling aspen (northern and western North America) Habitat and longevity The trembling of the leaves of the trembling aspen Aspen trees are all native to cold regions with cool summers, in the north of the northern hemisphere, extending south at high-altitude areas such as mountains or high plains. They are all medium-sized deciduous trees reaching tall. In North America, the aspen is referred to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picea Engelmannii
''Picea engelmannii'', with the common names Engelmann spruce, white spruce, mountain spruce, and silver spruce, is a species of spruce native to western North America. It is mostly a high-altitude mountain tree but also appears in watered canyons. Description ''Picea engelmannii'' is a medium-sized to large evergreen tree growing to tall, exceptionally to tall, and with a trunk diameter of up to . The reddish bark is thin and scaly, flaking off in small circular plates across. The crown is narrow conic in young trees, becoming cylindric in older trees. The shoots are buff-brown to orange-brown, usually densely pubescent, and with prominent pulvini. The leaves are needle-like, long, flexible, rhombic in cross-section, glaucous blue-green above with several thin lines of stomata, and blue-white below with two broad bands of stomata. The needles have a pungent odour when crushed. Purple cones of about 1 cm appear in spring, releasing yellow pollen when windy. The cones are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Populus Balsamifera
''Populus balsamifera'', commonly called balsam poplar, bam, bamtree, eastern balsam-poplar, hackmatack, tacamahac poplar, tacamahaca, is a tree species in the balsam poplar species group in the poplar genus, '' Populus.'' The genus name ''Populus'' is from the Latin for poplar, and the specific epithet ''balsamifera'' from Latin for "balsam-bearing". ''Populus balsamifera'' is the northernmost North American hardwood, growing transcontinentally on boreal and montane upland and flood plain sites, and attaining its best development on flood plains. It is a hardy, fast-growing tree which is generally short lived, but some trees as old as 200 years have been found. The tree is known for its strong, sweet fragrance, which emanates from its sticky, resinous buds. The smell has been compared to that of the balsam fir tree. Taxonomy The black cottonwood, ''Populus trichocarpa'', is sometimes considered a subspecies of ''P. balsamifera'' and may lend its common name to this species, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betula Papyrifera
''Betula papyrifera'' (paper birch, also known as (American) white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named for the tree's thin white bark, which often peels in paper like layers from the trunk. Paper birch is often one of the first species to colonize a burned area within the northern latitudes, and is an important species for moose browsing. The wood is often used for pulpwood and firewood. Description It is a medium-sized deciduous tree typically reaching tall, and exceptionally to with a trunk up to in diameter. Within forests, it often grows with a single trunk but when grown as a landscape tree it may develop multiple trunks or branch close to the ground. Paper birch is a typically short-lived species. It handles heat and humidity poorly and may live only 30 years in zones six and up, while trees in colder-climate regions can grow for more than 100 years. ''B. papyrifera'' will grow in many so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picea Mariana
''Picea mariana'', the black spruce, is a North American species of spruce tree in the pine family. It is widespread across Canada, found in all 10 provinces and all 3 territories. It is the official tree of the province of Newfoundland and Labrador and is that province's most numerous tree. The range of the black spruce extends into northern parts of the United States: in Alaska, the Great Lakes region, and the upper Northeast. It is a frequent part of the biome known as taiga or boreal forest.. The Latin specific epithet ''mariana'' means “of the Virgin Mary”. Description ''P. mariana'' is a slow-growing, small upright evergreen coniferous tree (rarely a shrub), having a straight trunk with little taper, a scruffy habit, and a narrow, pointed crown of short, compact, drooping branches with upturned tips. Through much of its range it averages tall with a trunk diameter at maturity, though occasional specimens can reach tall and diameter. The bark is thin, scaly, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abies Balsamea
''Abies balsamea'' or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Appalachian Mountains to West Virginia). Description Balsam fir is a small to medium-size evergreen tree typically tall, occasionally reaching a height of . The narrow conic crown consists of dense, dark-green leaves. The bark on young trees is smooth, grey, and with resin blisters (which tend to spray when ruptured), becoming rough and fissured or scaly on old trees. The leaves are flat and needle-like, long, dark green above often with a small patch of stomata near the tip, and two white stomatal bands below, and a slightly notched tip. They are arranged spirally on the shoot, but with the leaf bases twisted so that the leaves appear to be in two more-or-less horizontal rows on either side of the shoot. The needles become shorter and thicker the higher they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts 187 species names of pines as current, together with more synonyms. The American Conifer Society (ACS) and the Royal Horticultural Society accept 121 species. Pines are commonly found in the Northern Hemisphere. ''Pine'' may also refer to the lumber derived from pine trees; it is one of the more extensively used types of lumber. The pine family is the largest conifer family and there are currently 818 named cultivars (or trinomials) recognized by the ACS. Description Pine trees are evergreen, coniferous resinous trees (or, rarely, shrubs) growing tall, with the majority of species reaching tall. The smallest are Siberian dwarf pine and Potosi pinyon, and the tallest is an tall ponderosa pine located in southern Oregon's Rogue Riv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
