Hardwood

Hardwood is wood from deciduous trees and broad-leaf evergreen trees.^[1] All hardwoods are angiosperms (flowering plants), the largest group of land plants. Hardwood is contrasted to softwood, which comes from conifers, cone bearing seed plants. Hardwoods are not always harder than softwoods, balsa wood being an example of this.^[2] Hardwood trees are more varied than softwoods and there are about 100 times more species of hardwood than there are softwoods.^[3] Hardwoods usually have broad leaves. Hardwoods all have enclosed nuts or seeds, where softwoods are gymnosperms, naked seed plants.leis

Each species of hardwood has its own set of properties, however they have some properties in common. Hardwoods normally have broad leaves and come from deciduous or broad-leafed evergreen trees. Hardwoods grow slower than softwoods. Evergreen softwoods grow faster than deciduous hardwoods, and can grow to a larger size.^[4] Some hardwoods are excellent for carving. One of the hardest hardwoods is black ironwood which is recognized by the Guinness Book of World Records as the heaviest wood.^[5] Ironwoods are so dense that they sink in water rather than float as other woods do.^[6]

The properties of the wood are caused by its structure. Hardwoods have a denser structure, which is the reason they are usually harder and heavier. Hardwood has xylem vessels which are used to transport water. Their cell walls are strongly lignified: lignin is a hard material used to support plants above the surface. The quantity of lignin is probably the main factor in their hardness.

Softwoods have a vascular structure which looks similar to a bunch of drinking straws held together. They also have lignin, but of a slightly different type, and less of it than most hardwoods.

1. ↑ Izzy (2008-02-12). "Hardwoods". Camberwell Material Library. Archived from the original on October 28, 2011. Retrieved October 15, 2011.
2. ↑ "Hardwoods". www.mr-dt.com. Retrieved October 16, 2011.
3. ↑ ^{3.0 3.1} Coombes, Allen J. (2010). The illustrated Encyclopedia of Trees and Shrubs. Salamander Books. ISBN 978-1840651621.
4. ↑ "Year 10 Manufacturing (Resistant Materials)". Design Technology Department. Retrieved October 16, 2011.
5. ↑ "Botanical Record Breakers - Part 1 of 2". Palomar College. Archived from the original on December 19, 2010. Retrieved October 17, 2011.
6. ↑ W.P. Armstrong (2010-04-28). "Hardwoods Trees & Shrubs With Dense, Hard Wood". Palomar College. Archived from the original on July 26, 2014. Retrieved October 17, 2011.