Changes

Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in the [[forest]], and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferred. This is particularly the case in the choice of hickory for handles and [[spoke]]s. Here not only strength, but toughness and resilience are important. The results of a series of tests on hickory by the U.S. Forest Service show that:  

Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in the [[forest]], and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferred. This is particularly the case in the choice of hickory for handles and [[spoke]]s. Here not only strength, but toughness and resilience are important. The results of a series of tests on hickory by the U.S. Forest Service show that:  

:"The work or shock-resisting ability is greatest in wide-ringed wood that has from 5 to 14 rings per [[inch]] (rings 1.8-5 [[millimetre|mm]] thick), is fairly constant from 14 to 38 rings per inch (rings 0.7-1.8 mm thick), and decreases rapidly from 38 to 47 rings per inch (rings 0.5-0.7 mm thick). The strength at maximum load is not so great with the most rapid-growing wood; it is maximum with from 14 to 20 rings per inch (rings 1.3-1.8 mm thick), and again becomes less as the wood becomes more closely ringed. The natural deduction is that wood of first-class mechanical value shows from 5 to 20 rings per inch (rings 1.3-5 mm thick) and that slower growth yields poorer stock. Thus the

:"The work or shock-resisting ability is greatest in wide-ringed wood that has from 5 to 14 rings per [[inch]] (rings 1.8-5 [[millimetre|mm]] thick), is fairly constant from 14 to 38 rings per inch (rings 0.7-1.8 mm thick), and decreases rapidly from 38 to 47 rings per inch (rings 0.5-0.7 mm thick). The strength at maximum load is not so great with the most rapid-growing wood; it is maximum with from 14 to 20 rings per inch (rings 1.3-1.8 mm thick), and again becomes less as the wood becomes more closely ringed. The natural deduction is that wood of first-class mechanical value shows from 5 to 20 rings per inch (rings 1.3-5 mm thick) and that slower growth yields poorer stock. Thus the inspector or buyer of hickory should discriminate against timber that has more than 20 rings per inch (rings less than 1.3 mm thick). Exceptions exist, however, in the case of normal growth upon dry situations, in which the slow-growing material may be strong and tough."<ref name=USforest>U.S. Department of Agriculture, Forest Products Laboratory. ''[http://www.fpl.fs.fed.us/documn/ts/fplgtr/fplgtr113/fplgtr113.htm The Wood Handbook: Wood as an engineering material]''.  General Technical Report 113. Madison, WI.</ref>

inspector or buyer of hickory should discriminate against timber that has more than 20 rings per inch (rings less than 1.3 mm thick). Exceptions exist, however, in the case of normal growth upon dry situations, in which the slow-growing material may be strong and tough."<ref name=USforest>U.S. Department of Agriculture, Forest Products Laboratory. ''[http://www.fpl.fs.fed.us/documn/ts/fplgtr/fplgtr113/fplgtr113.htm The Wood Handbook: Wood as an engineering material]''.  General Technical Report 113. Madison, WI.</ref>

The effect of rate of growth on the qualities of chestnut wood is summarized by the same authority as follows:

The effect of rate of growth on the qualities of chestnut wood is summarized by the same authority as follows: