. Defects in timber caused by insects. Wood; Forest insects. DEFECTS IN TIMBER CAUSED BY INSECTS 17 rejected for barrel staves and heads of tight cooperage, unless the holes are few and can be plugged. Such stock can be used where the holes can be plugged, puttied, and painted over, or as a base for veneer. Pinholes or worm- holes one one-hun- dredth to three-six- teenths of an inch in diameter in green saw logs with the bark on, of basswood, buckeye, chestnut, black wal- nut, cottonwood, yel- low poplar, and birch (fig. 17), are caused by the sapwood tim- ber worm,11 which may cause a 5 to 10
. Defects in timber caused by insects. Wood; Forest insects. DEFECTS IN TIMBER CAUSED BY INSECTS 17 rejected for barrel staves and heads of tight cooperage, unless the holes are few and can be plugged. Such stock can be used where the holes can be plugged, puttied, and painted over, or as a base for veneer. Pinholes or worm- holes one one-hun- dredth to three-six- teenths of an inch in diameter in green saw logs with the bark on, of basswood, buckeye, chestnut, black wal- nut, cottonwood, yel- low poplar, and birch (fig. 17), are caused by the sapwood tim- ber worm,11 which may cause a 5 to 10 per cent loss of a log. This defect is de- scribed as " worm- holes, no living worms or decay," and can be prevented. The insect lays its eggs in dying trees and green saw logs which are allowed to lie in the woods with the bark on from April to July, in the States north of the Gulf. The eggs are deposited in crevices in the bark. The beetle will not lay its eggs in barked logs or logs which are floating in log ponds. In the sapwood or heartwood of oak, ma- ple, tupelo gum, and beech, grouped holes from one-eighth to three-sixteenths of an inch in diameter and all more or less connected by irregular blackened streaks are caused by tenebrionid timber ^Hylecoetus lugiibris Say. 12 The larvae of Strongylium spp. cause wormholes in hardwoods. 38252°—27 3. Fig. 18.—Holes caused by termites (Coptotermes niger) in log imported from Honduras ; damage to the living tree caused this defect in the board. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Snyder, Thomas Elliott, b. 1885. Washington, D. C. : U. S. Dept. of Agriculture
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherwa, booksubjectwood
