This article includes a list of general references, but it lacks sufficient corresponding inline citations .(January 2010) |
The crown of a plant is the total of an individual plant's aboveground parts, including stems, leaves, and reproductive structures. A plant community canopy consists of one or more plant crowns growing in a given area.
The crown of a woody plant (tree, shrub, liana) is the branches, leaves, and reproductive structures extending from the trunk or main stems.
Shapes of crowns are highly variable. The major types for trees are the excurrent branching habit resulting in conoid shapes and decurrent (deliquescent) branching habit, resulting in round shapes. Crowns are also characterized by their width, depth, surface area, volume, and density. Measurements of crowns are important in quantifying and qualifying plant health, growth stage, and efficiency.
Major functions of the crown include light energy assimilation, carbon dioxide absorption and release of oxygen via photosynthesis, energy release by respiration, and movement of water to the atmosphere by transpiration. These functions are performed by the leaves.
Trees can be described as fitting different crown classes. Commonly used are Kraft's classes. [1] Kraft designated these "social classes" based on temperate and boreal forests in Central Europe, so they do not necessarily work with every forest type in the world.
Kraft wrote in German so here are his classes with translations:
Often it has been simplified to Dominant, Co-dominant and Suppressed. [2]
Also IUFRO developed a tree classification it is based on three components with numbers that then aggregate to give a coded classification thus: [3]
Ecological criteria
Height component (Stand layer / Height class):
Vitality component (Tree vigor / vitality):
Future growth potential component (Developmental tendency / conversion tendency):
and then additionally
Silvicultural criteria
Commercial worth
Trunk class
Crown class
While both Kraft and IUFRO classifications are aimed at describing individual tree crowns both can and are applied to describe whole layers or storeys. [4]
Wood is a structural tissue found in the stems and roots of trees and other woody plants. It is an organic material – a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or more broadly to include the same type of tissue elsewhere, such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, woodchips, or fiber.
Forestry is the science and craft of creating, managing, planting, using, conserving and repairing forests and woodlands for associated resources for human and environmental benefits. Forestry is practiced in plantations and natural stands. The science of forestry has elements that belong to the biological, physical, social, political and managerial sciences. Forest management plays an essential role in the creation and modification of habitats and affects ecosystem services provisioning.
Eucalyptus regnans, known variously as mountain ash, giant ash or swamp gum, or stringy gum, is a species of very tall forest tree that is native to the Australia states of Tasmania and Victoria. It is a straight-trunked tree with smooth grey bark, but with a stocking of rough brown bark at the base, glossy green, lance-shaped to curved adult leaves, flower buds in groups of between nine and fifteen, white flowers, and cup-shaped or conical fruit. It is the tallest of all flowering plants; the tallest measured living specimen, named Centurion, stands 100 metres tall in Tasmania.
Agathis australis, or kauri, is a coniferous tree in the family Araucariaceae, found north of 38°S in the northern regions of New Zealand's North Island.
Acer rubrum, the red maple, also known as swamp maple, water maple, or soft maple, is one of the most common and widespread deciduous trees of eastern and central North America. The U.S. Forest Service recognizes it as the most abundant native tree in eastern North America. The red maple ranges from southeastern Manitoba around the Lake of the Woods on the border with Ontario and Minnesota, east to Newfoundland, south to Florida, and southwest to East Texas. Many of its features, especially its leaves, are quite variable in form. At maturity, it often attains a height around 30 m (100 ft). Its flowers, petioles, twigs, and seeds are all red to varying degrees. Among these features, however, it is best known for its brilliant deep scarlet foliage in autumn.
Pruning is a horticultural, arboricultural, and silvicultural practice involving the selective removal of certain parts of a plant, such as branches, buds, or roots.
Thinning is a term used in agricultural sciences to mean the removal of some plants, or parts of plants, to make room for the growth of others. Selective removal of parts of a plant such as branches, buds, or roots is typically known as pruning.
Tsuga heterophylla, the western hemlock or western hemlock-spruce, is a species of hemlock native to the west coast of North America, with its northwestern limit on the Kenai Peninsula, Alaska, and its southeastern limit in northern Sonoma County, California. The Latin species name means 'variable leaves'.
Forest ecology is the scientific study of the interrelated patterns, processes, flora, fauna, funga, and ecosystems in forests. The management of forests is known as forestry, silviculture, and forest management. A forest ecosystem is a natural woodland unit consisting of all plants, animals, and micro-organisms in that area functioning together with all of the non-living physical (abiotic) factors of the environment.
Torreya californica is a species of conifer endemic to California, occurring in the Pacific Coast Ranges and the foothills of the Sierra Nevada. It is commonly known as California torreya or California nutmeg tree. It is one of only two species of genus Torreya that are native to North America. A slow-growing subcanopy tree, it is listed as "vulnerable" in the IUCN Red List.
Anodopetalum biglandulosum is a Tasmanian endemic shrub or small tree species that is a common component of Tasmania's cool temperate rainforests. It is commonly known as horizontal because of its habit of growth. It is the sole species in the genus Anodopetalum.
Agathis macrophylla known as Pacific kauri, is a coniferous tree native to the islands of the southwestern Pacific Ocean in tropical humid lowlands and lower montane regions, notably in Fiji, Vanuatu, and the Santa Cruz Islands. The Pacific kauri is one of the largest and fastest growing species in its genus, and is important in forestry.
The following outline is provided as an overview of and guide to forestry:
Syncarpia glomulifera, commonly known as the turpentine tree, or yanderra, is a tree of the family Myrtaceae native to New South Wales and Queensland in Australia, which can reach 60 metres in height. It generally grows on heavier soils. The cream flowers appear in spring and are fused into compound flowerheads.
Eucalyptus botryoides, commonly known as the bangalay, bastard jarrah, woollybutt or southern mahogany, is a small to tall tree native to southeastern Australia. Reaching up to 40 metres high, it has rough bark on its trunk and branches. It is found on sandstone- or shale-based soils in open woodland, or on more sandy soils behind sand dunes. The white flowers appear in summer and autumn. It reproduces by resprouting from its woody lignotuber or epicormic buds after bushfire. E. botryoides hybridises with the Sydney blue gum in the Sydney region. The hard, durable wood has been used for panelling and flooring.
Lepidodendrales or arborescent lycophytes are an extinct order of primitive, vascular, heterosporous, arborescent (tree-like) plants belonging to Lycopodiopsida. Members of Lepidodendrales are the best understood of the fossil lycopsids due to the vast diversity of Lepidodendrales specimens and the diversity in which they were preserved; the extensive distribution of Lepidodendrales specimens as well as their well-preservedness lends paleobotanists exceptionally detailed knowledge of the coal-swamp giants’ reproductive biology, vegetative development, and role in their paleoecosystem. The defining characteristics of the Lepidodendrales are their secondary xylem, extensive periderm development, three-zoned cortex, rootlike appendages known as stigmarian rootlets arranged in a spiralling pattern, and megasporangium each containing a single functional megaspore that germinates inside the sporangium. Many of these different plant organs have been assigned both generic and specific names as relatively few have been found organically attached to each other. Some specimens have been discovered which indicate heights of 40 and even 50 meters and diameters of over 2 meters at the base. The massive trunks of some species branched profusely, producing large crowns of leafy twigs; though some leaves were up to 1 meter long, most were much shorter, and when leaves dropped from branches their conspicuous leaf bases remained on the surface of branches. Strobili could be found at the tips of distal branches or in an area at the top of the main trunk. The underground organs of Lepidodendrales typically consisted of dichotomizing axes bearing helically arranged, lateral appendages serving an equivalent function to roots. Sometimes called "giant club mosses", they are believed to be more closely related to extant quillworts based on xylem, although fossil specimens of extinct Selaginellales from the Late Carboniferous also had secondary xylem.
A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to herbaceous plants that die back to the ground until spring.
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees.
Eucalyptus pilularis, commonly known as blackbutt, is a species of medium-sized to tall tree that is endemic to eastern Australia. It has rough, finely fibrous greyish bark on the lower half of the trunk, smooth white, grey or cream-coloured bark above, lance-shaped to curved adult leaves, flower buds in groups of between seven and fifteen, white flowers and hemispherical or shortened spherical fruit.
Pseudotsuga menziesii var. menziesii, commonly known as Coast Douglas-fir, Pacific Douglas-fir, Oregon pine, or Douglas spruce, is an evergreen conifer native to 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 Coast Ranges and Pacific Ocean. In California, it is found in the Klamath and California Coast Ranges as far south as the Santa Lucia Mountains with a small stand as far south as the Purisima Hills, Santa Barbara County. In the Sierra Nevada it ranges as far south as the Yosemite region. It occurs from near sea level along the coast to 1,800 metres (5,900 ft) in the California Mountains. Further inland, coast Douglas-fir is replaced by Rocky Mountain or interior Douglas-fir. Interior Douglas-fir intergrades with coast Douglas-fir in the Cascades of northern Washington and southern British Columbia.
{{cite web}}
: CS1 maint: archived copy as title (link)