. Department bulletin. Agriculture; Agriculture. 20 BULLETIN 1128, U. S. DEPARTMENT OF AGRICULTURE. SAPSUCKER WOUNDS. Sapsuckers arc a group of woodpeckers which extract the sap from the inner bark and sapwood of living trees and eat the cambium. The final result after the wound has healed or callused over is the so-called bird pecks (15, 35). This injury is often accompanied by extensive staining, particularly in the hardwoods. On the ends of logs or boards the healed wounds appear as stained areas of varying size, each containing a more or less open, short, radial check in con- nection with
. Department bulletin. Agriculture; Agriculture. 20 BULLETIN 1128, U. S. DEPARTMENT OF AGRICULTURE. SAPSUCKER WOUNDS. Sapsuckers arc a group of woodpeckers which extract the sap from the inner bark and sapwood of living trees and eat the cambium. The final result after the wound has healed or callused over is the so-called bird pecks (15, 35). This injury is often accompanied by extensive staining, particularly in the hardwoods. On the ends of logs or boards the healed wounds appear as stained areas of varying size, each containing a more or less open, short, radial check in con- nection with distorted grain. The general appearance is a T-shaped or triangular mark or check surrounded by a stain varying from brown to almost black. More than one usually occurs in the same annual ring. On the edge-grain or slash-grain faces of sawed lumber these injuries usually appear as small knots or distortions in the grain, surrounded by more or less stain which is usually localized, but the stain may be accompanied by a bleaching which extends for some distance. The stain is always adjacent to the distorted grain, and the more distorted the grain the greater the extent of the stain. The stain appears to be the most injurious of the two, but in reality the distorted grain is the only cause of weakening in the wood. The strength of the wood is not much affected, so that wood with bird pecks in most cases can be safely utilized. Figure 6 shows a sec- tion from a white-ash longeron with a minor injury of this kind which does not impair the usefulness of the member. Pieces are some-. fig. 6. — Section from a times unsuitable for handles, owing to the fnngisaedsapsucker' injury tendency of the grain to roughen up at these ashbird peck in white places when planed. If the pecks are nu- merous in one annual ring it is best not to use the piece, for although it has not been determined by comparative tests it is quite probable that such material is reduced in strength. Checks or wind-shak
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