Does wood from the upper part of a horizontal tree branch, which is under tension, have different characteristics to that from the lower part, which is under compression? Is wood ever selected for a purpose on the basis of such differences?
(Continued)
鈥� A good example of something that takes advantage of the tension and compression properties of wood is the traditional longbow 鈥� although that wood comes from the trunk. The living sapwood stretches, so forms the outside or back of the bow stave, whereas the dead heartwood goes on the inside, or belly, of the stave, and resists compression.
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The English longbow was traditionally made from Spanish or Italian yew, which carried less water than English yew. This possibly gave us the posh word for archery 鈥� toxophily 鈥� because the yew (Taxus baccata) that bows are made of is poisonous.
Dave Hulme, Stockport, Greater Manchester, UK
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