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Wood ash from a campfire. Wood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant.It is largely composed of calcium compounds, along with other non-combustible trace elements present in the wood, and has been used for many purposes throughout history.
NCSU Inside Wood project Reproduction of The American Woods: exhibited by actual specimens and with copious explanatory text by Romeyn B. Hough US Forest Products Laboratory, "Characteristics and Availability of Commercially Important Wood" from the Wood Handbook Archived 2021-01-18 at the Wayback Machine PDF 916K
Fraxinus americana, the white ash or American ash, is a fast-growing species of ash tree native to eastern and central North America. White ash trees are threatened by the invasive emerald ash borer .
Native ash species, including white ash (pictured), have been declining rapidly this century due to predation by the emerald ash borer. [1] Silvics of North America (1991), [2] [3] a forest inventory compiled and published by the United States Forest Service, includes many hardwood trees.
It is common to classify wood as either softwood or hardwood. The wood from conifers (e.g. pine) is called softwood, and the wood from dicotyledons (usually broad-leaved trees, e.g. oak) is called hardwood. These names are a bit misleading, as hardwoods are not necessarily hard, and softwoods are not necessarily soft.
Its wood has an average crush strength of 8,140 lb/in 2 (56.1 MPa), which exceeds many hardwoods such as white ash (7,410 lb/in 2) and black maple (6,680 lb/in 2). It is not as strong as black ironwood (9,940 lb/in 2 ), but because its average density is less than half that of ironwood, slash pine has a far greater strength-to-weight ratio.
The following table associates tree species, wood name and wood colour. The Dipterocarp timber classification system was developed by Colin Fraser Symington (1905-1943), a forester at the Malayan Forestry Service, and H. E. Desch, who researched comparative wood anatomy.
The hardest hardwoods are much harder than any softwood, [4] but in both groups there is enormous variation with the range of wood hardness of the two groups overlapping. For example, balsa wood, which is a hardwood, is softer than most softwoods, whereas the longleaf pine, Douglas fir, and yew softwoods are much harder than several hardwoods.