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Different types of wood (list of names on description page)

WoodFrom Wikipedia, the free encyclopedia

Wood is a hard, fibrous structural tissue found inthe stems and roots of trees and other woodyplants. It has been used for thousands of years forboth fuel and as a construction material. It is anorganic material, a natural composite of cellulosefibers (which are strong in tension) embedded in amatrix of lignin which resists compression. Wood issometimes defined as only the secondary xylem inthe stems of trees,[1] or it is defined more broadlyto include the same type of tissue elsewhere such asin the roots of trees or shrubs. In a living tree itperforms a support function, enabling woody plantsto grow large or to stand up by themselves. It alsomediates the transfer of water and nutrients to theleaves and other growing tissues. Wood may alsorefer to other plant materials with comparableproperties, and to material engineered from wood,or wood chips or fiber.

The Earth contains about one trillion tonnes ofwood, which grows at a rate of 10 billion tonnesper year. As an abundant, carbon-neutralrenewable resource, woody materials have been ofintense interest as a source of renewable energy. In1991, approximately 3.5 billion cubic meters ofwood were harvested. Dominant uses were forfurniture and building construction.[2]

Contents

1 History2 Physical properties

2.1 Growth rings2.2 Knots2.3 Heartwood and sapwood2.4 Color2.5 Water content2.6 Structure

2.6.1 Earlywood and latewood in softwood

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2.6.2 Earlywood and latewood in ring-porous woods2.6.3 Earlywood and latewood in diffuse-porous woods

2.7 Monocot wood3 Hard and soft woods4 Chemistry of wood

4.1 Extractives5 Uses

5.1 Fuel5.2 Construction

5.2.1 Wood flooring5.2.2 Engineered wood

5.3 Furniture and utensils5.4 Next generation wood products5.5 In the arts5.6 Sports and recreational equipment5.7 Medicine

6 Bacterial Degradation7 See also8 References9 Footnotes10 External links

History

A 2011 discovery in the Canadian province of New Brunswick uncovered the earliest known plants to have grownwood, approximately 395 to 400 million years ago.[3]

People have used wood for millennia for many purposes, primarily as a fuel or as a construction material for makinghouses, tools, weapons, furniture, packaging, artworks, and paper.

Wood can be dated by carbon dating and in some species by dendrochronology to make inferences about when awooden object was created.

The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at thattime.[4]

Physical properties

Growth rings