Hardwood
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The term hardwood designates wood from broad-leaved (mostly deciduous, but not necessarily, in the case of tropical trees) or angiosperm trees. Hardwood contrasts with softwood, which comes from conifer trees. On average, hardwood is of higher density and hardness than softwood, but there is considerable variation in actual wood hardness in both groups, with a large amount of overlap; some hardwoods (e.g. balsa) are softer than most softwoods, while yew is an example of a hard softwood. Hardwoods have broad leaves and enclosed nuts or seeds such as acorns. They often grow in subtropical regions like Africa and also in Europe and other regions such as Asia.
Hardwood species are more varied than softwood. There are about a hundred times as many hardwood species than there are softwoods. The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall (e.g. spiral thickenings).
Hardwoods serve an enormous range of applications, including buildings, furniture, flooring, utensils, etc.
Hardwoods are generally far more resistant to decay than softwoods when used for exterior work. However, solid hardwood joinery is expensive compared to softwood (in the past, tropical hardwoods were easily available but the supply is now restricted due to sustainability issues) and most "hardwood" doors, for instance, now consist of a thin veneer bonded to medium-density fibreboard (MDF).
A recently classified hardwood is Palmwood, which comes from the monocotyledon group of plants and is being promoted as a sustainable alternative to the shrinking stocks of "conventional" hardwoods.
[edit] See also
[edit] References
- Schweingruber, F.H. (1990) Anatomie europäischer Hölzer—Anatomy of European woods. Eidgenössische Forschungsanstalt für Wald, Schnee und Landscaft, Birmensdorf (Hrsg,). Haupt, Bern und Stuttgart.
- Timonen, Tuuli (2002). Introduction to Microscopic Wood Identification. Finnish Museum of Natural History, University of Helsinki.
- Wilson, K., and D.J.B. White (1986). The Anatomy of Wood: Its Diversity and variability. Stobart & Son Ltd, London.
