. Defects in timber caused by insects. Wood; Forest insects. DEFECTS IN TIMBER CAUSED BY INSECTS 11 stained, or with short streaks in the surrounding wood; these holes run deeply in every direction in an irregular manner through the wood, and it is difficult to determine their extent from the surface. The}7 are termed "pinholes," "shot holes," or "black holes" (36). Such holes occur in both the sapwood and heartwood of softwoods and hardwoods, but are more common in the sapwood. One of the commonest defects (fig. 1) is caused in living trees by an ambrosia beetle,
. Defects in timber caused by insects. Wood; Forest insects. DEFECTS IN TIMBER CAUSED BY INSECTS 11 stained, or with short streaks in the surrounding wood; these holes run deeply in every direction in an irregular manner through the wood, and it is difficult to determine their extent from the surface. The}7 are termed "pinholes," "shot holes," or "black holes" (36). Such holes occur in both the sapwood and heartwood of softwoods and hardwoods, but are more common in the sapwood. One of the commonest defects (fig. 1) is caused in living trees by an ambrosia beetle,2 and the holes are known as " black holes," " spot worm," "steamboats,". fc*-'5' fi " grease spots " (West Vir- ginia), and "flag worm'' (Arkansas). The holes usually occur in the best part of the wood, either one in a place, or two or more in a row. This de- fect is so prevalent in ma- ture white oak and other oaks that it is often diffi- cult to find a tree the wood of which is entirely free from it; in yellow poplar the defect is not so com- mon. When the defect does occur in whitewood or yellow poplar the ac- companying long, black, greenish or bluish streaks give a calico effect, and the wood is called " calico pop- lar " (fig. 2) (23,27). The same defect occurs in beech, birch, basswood. maple, and elm in West Virginia, elm and oak in Michigan, oak in Arkan- sas, and chestnut in Ten- nessee. Calico poplar and oak might be used, when avail- able in sufficient quantity, as a special grade for in- terior natural-wood finish, as the effect is pleasing. Thus the apparently limited quantity could be utilized without hav- ing its value depreciated much below that of the first and second grades. This defect causes a serious loss to stave and shingle stock. In Arkansas from 30 to 40 per cent of white oak Bourbon whisky-barrel- stave stock and staves has often been left to rot in the woods on account of injury by the oak timbe
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherwa, booksubjectwood
