Wood

== Description ==
The hard, fibrous tissue composing the trunk, branches, and roots of trees and shrubs. Wood is a renewable resource that is abundantly available and versatile in its usefulness. It has been used for tools, structures, and as an art material since earliest times. Wood is primarily composed of cellulose (40-60% ) and hemicelluloses (15-25%) embedded in a matrix of lignin (15-40%). It can also contain resins, dyes, tannins, waxes, and oils. Wood is still used throughout the world for lumber, furniture, paper, pulp, and fuel. Over 3000 species of plants, primarily trees, produce wood. They are categorized as either hardwood (angiosperm) or softwood (gymnosperm) trees. Identification and characterization of wood are based on the following properties (Gettens and Stout 1966): 
* Annual leaf, flower and fruit formation and release (deciduous or evergreen)
* Color of heartwood (interior mature wood) and sapwood (outer actively growing wood). 
* Visibility and size of growth rings 
* Cell size and variation for spring wood (formed at the beginning of the growing season) and summerwood (formed at the end of the growing season). 
* Size and number of medullary rays 
* Pore size and distribution. 
Examples of hardwoods include: Ash, aspen, alder basswood, beech, Birch, Cherry, chestnut, elm, fruitwood, Hackberry, hazel, hickory, holly, lacewood, linden, Locust, magnolia, mahogany, maple, mulberry, oak, olive, poplar, rosewood, satinwood, Sweetgum, sycamore, teak, tupelo, walnut, willow.
Examples of softwoods include: Cedar, cypress, fir, larch, pine, redwood, spruce
The age of wood can be determined by carbon dating (measurement of its isotopic composition) and/or by dendrochronology (measurement of the pattern of tree-ring widths). 
For detailed information on wood usage, properties and care, please see the AIC Wikis for:
* Wood (Objects Specialty Group): Wood
* Wooden Artifacts (Wooden Artifacts Group): Wooden Artifacts 
== Synonyms and Related Terms ==
lumber; bois (Fr.); madera (Esp.); madeira (Port.); legno (It.)
==Risks==
Wood is deteriorated by primarily by insect and microbiological infestations. 
== Physical and Chemical Properties ==
Insoluble in water and organic solvents, but will swell and absorb most liquids.
== Resources and Citations ==
* The Wood Database: website
* Alden Identification Services, Microscopic Wood Identification: Link
* Wikipedia: Wood Accessed October 2024, the site provide extensive information on the structure, characteristics, properties (physical and chemical) and usage for many types of wood.
* Encyclopedia Britannica, http://www.britannica.com Comment: "wood" [Accessed November 7, 2001].
* R. Bruce Hoadley, Identifying Wood, The Taunton Press, Newton, CT, 1990
* R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
* G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 874
* Hermann Kuhn, Conservation and Restoration of Works of Art and Antiquities, Butterworths, London, 1986
* Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
* Pam Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002
Category:Materials databaseCategory:MWGCategory: Wood