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Hardwood
Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Characteristics Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual growth rings, but these may be absent in some tropical hardwoods. Hardwoods have a more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods is the presence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala 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 it is defined 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, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Softwood
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 yew are much harder in the mechanical sense than several hardwoods. Softwoods are generally most used by the construction industry and are also used to produce paper pulp, and ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala 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 it is defined 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, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemicellulose
A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all terrestrial plant cell walls.Scheller HV, Ulvskov Hemicelluloses.// Annu Rev Plant Biol. 2010;61:263-89. doi: 10.1146/annurev-arplant-042809-112315. Cellulose is crystalline, strong, and resistant to hydrolysis. Hemicelluloses are branched, shorter in length than cellulose, and also show a propensity to crystallize. They can be hydrolyzed by dilute acid or base as well as a myriad of hemicellulase enzymes. Composition Diverse kinds of hemicelluloses are known. Important examples include xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan. Hemicelluloses are polysaccharides often associated with cellulose, but with distinct compositions and structures. Whereas cellulose is derived exclusively from glucose, hemicelluloses are composed of diverse sugars, and can include the five-carbon sugars xy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vessel Element
A vessel element or vessel member (also called trachea or xylem vessel) is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in angiosperms (flowering plants) but absent from most gymnosperms such as conifers. Vessel elements are the main feature distinguishing the " hardwood" of angiosperms from the " softwood" of conifers. Morphology Xylem is the tissue in vascular plants that conducts water (and substances dissolved in it) upwards in a plant. There are two kinds of cell that are involved in the actual transport: tracheids and vessel elements. Tracheids & vessel elements make the tracheary elements of xylem.Vessel elements are the building blocks of vessels, which constitute the major part of the water transporting system in those plants in which they occur. Vessels form an efficient system for transporting water (including necessary minerals) from the root to the leaves and other parts of the plant. In seco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree
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. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight. The majority of tree species are angiosperms or hardwoods; of the rest, many are gymnosperms or softwoods. Trees tend to be long-lived, some reaching several thousand years old. Trees have been in existence for 370 million years. It is estimated that there are some three trillion mature trees in the world. A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ochroma Pyramidale
''Ochroma pyramidale'', commonly known as the balsa tree, is a large, fast-growing tree native to the Americas. It is the sole member of the genus ''Ochroma''. The tree is famous for its wide usage in woodworking, with the name ''balsa'' being the Spanish word for "raft." A deciduous angiosperm, ''Ochroma pyramidale'' can grow up to 30 m tall, and is classified as a hardwood despite the wood itself being very soft; it is the softest commercial hardwood and is widely used because of its light weight. Biology Balsa on Bota Hill, Limbe Botanical Garden, Cameroon">Limbe_Botanical_Garden.html" ;"title="Bota Hill, Limbe Botanical Garden">Bota Hill, Limbe Botanical Garden, Cameroon A member of the mallow family, ''Ochroma pyramidale'' is native from southern Mexico to southern Brazil, but can now be found in many other countries (Papua New Guinea, Indonesia, Thailand, Solomon Islands). It is a pioneer plant, which establishes itself in clearings in forests, either man-made ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxus
''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish bark, lanceolate, flat, dark-green leaves long and broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem. The oldest known fossil species are from the Early Cretaceous. Morphology The seed cones are highly modified, each cone containing a single seed long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, long and wide and open at the end. The arils are mature 6–9 months after pollination, and with the seed contained are eaten by thrushes, waxwings and other birds, which disperse the hard seeds undamaged in their droppings; maturation of the arils is spread over 2–3 months, increasing the chances of successful ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%. Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a wide variety of derivative products such as cellophane and rayon. Conversion of cellulose from energy crops into biofuels such as cellulosic ethanol is under development as a renewable fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton. Some animals, particularly ruminants and termites, can digest cellulos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fagus Wood
Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engleriana'' subgenus is found only in East Asia, distinctive for its low branches, often made up of several major trunks with yellowish bark. The better known ''Fagus'' subgenus beeches are high-branching with tall, stout trunks and smooth silver-grey bark. The European beech (''Fagus sylvatica'') is the most commonly cultivated. Beeches are monoecious, bearing both male and female flowers on the same plant. The small flowers are unisexual, the female flowers borne in pairs, the male flowers wind-pollinating catkins. They are produced in spring shortly after the new leaves appear. The fruit of the beech tree, known as beechnuts or mast, is found in small burrs that drop from the tree in autumn. They are small, roughly triangular, and edible, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance “lignine”, which is derived from the Latin word ''lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose. Lignin constitutes 30% of non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor of plants and red algae als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropical Timber
Tropical timber may refer to any type of timber or wood that grows in tropical rainforests and tropical and subtropical moist broadleaf forests and is Harvester (forery), harvested there. Typical examples of worldwide industrial significance include, among others, the following hardwoods: *Mahogany *Teak *Ebony *Rosewood *Pterocarpus indicus, Narra *Chloroxylon Overexploitation of those woods has led to widespread tropical deforestation, deforestation in the tropics. The intergovernmental organization International Tropical Timber Organization is concerned with ecological conservation, conservation of the habitats of tropical timber trees. See also * International Tropical Timber Agreement, 2006 * Tropical Timber 94 * Tropical Timber 83 * Tropical Forest Trust * Forest Stewardship Council * CITES * tropical forest * forestry * Plant Resources of Tropical Africa References Forestry Timber industry Tropical and subtropical moist broadleaf forests {{forestry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
