Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Hardwood
Summary
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).
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 of pores, or vessels. The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall, such as spiral thickenings.
As the name suggests, the wood from these trees is generally harder than that of softwoods, but there are significant exceptions. In both groups there is an enormous variation in actual wood hardness, with the range in density in hardwoods completely including that of softwoods; some hardwoods (e.g., balsa) are softer than most softwoods, while yew is an example of a hard softwood.
The structural polymers of hardwoods are cellulose, hemicellulose, and lignin. The constituents of hardwood lignin differs from those included in softwood. Sinapyl alcohol and coniferyl alcohol are the main monomers of hardwood lignin.
Hardwoods contain less amount of non-structural constituents, named extractives, than softwoods. These extractives are usually categorized into three broad groups: aliphatic compounds, terpenes and phenolic compounds.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.