. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 40 BULL! n S I I 0, 17. -. Dl PAH I M i N i 0] \«.l:i11111n»n defect. Timber from softwoods or hardwoods is not seriously reduced in strength by such defects, hut the wood is Lowered in grade and rendered useless for finishing, turning, staves, and woodenware. It can, however, be used for structural material or for purposes for â which the marred appearance will not be detrimental. Sine- black check is always the result of injury t the living tree, it is act preventable, from the 1 u ni be rman 's standpoint. DEFECTS
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 40 BULL! n S I I 0, 17. -. Dl PAH I M i N i 0] \«.l:i11111n»n defect. Timber from softwoods or hardwoods is not seriously reduced in strength by such defects, hut the wood is Lowered in grade and rendered useless for finishing, turning, staves, and woodenware. It can, however, be used for structural material or for purposes for â which the marred appearance will not be detrimental. Sine- black check is always the result of injury t the living tree, it is act preventable, from the 1 u ni be rman 's standpoint. DEFECTS CLASSED AS BLUING OR STAINING B1u ish-black streaks or stains in the sapwood of pine, especially in southern yellow, western yel- low, and sugar pine-. as well as in certain hardwoods, such as red gum or sap gum, are classed as hitting. This defect oee u rs either in the standing tree or in recently cut green logs or green lumber and is caused by fungi de- veloping from spores which are no doubt carried by insects. In pines the bluing directly follows in- festation by tree-killing bark beetles'11 in the standing trees (fig. 44) {29). This defect can be prevented only by the control of tree-killing bark beetles. Similar staining defects are caused by many ambrosia beetles42 in both the living trees and green saw logs and green, freshly sawn lumber. (Figs. 4, 9, and 13.) This staining can be prevented in green saw logs by prompt utilization of the green logs; by placing them in the mill pond soon after cutting; or by sun-curing. When the lumber is sawn it should be either kiln-dried or air-seasoned rapidly. Bluing is not always dependent on bark beetles (4$).. I'io. -Black cheek, in oak, mused by round-headed borer (Ooea sp.) in the living tree. The wound has healed over 41 Dendroctonus spp. Gnathotrlchus, Xyleborus, Platypus, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an
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