. Bulletin - Biological Survey. Zoology, Economic. 64 W00DPECKEES IN RELATION TO TREES. White fir (Abies concolor).—The defects are one-fourth to 1 inch long, filled with resin deposit and giving rise to fat streaks extending a foot or more along the grain. Many layers of wood over the wound have curly grain. The blemishes are of no consequence for coarse structural work, but destroy the value of the wood for ornamental purposes (Oregon, A. M. 444). Western hemlock (Tsuga heteropTiylla).—A specimen of this wood collected at Detroit, Oreg. (H.), shows reddish to black resinous scars 1 to 3| inc
. Bulletin - Biological Survey. Zoology, Economic. 64 W00DPECKEES IN RELATION TO TREES. White fir (Abies concolor).—The defects are one-fourth to 1 inch long, filled with resin deposit and giving rise to fat streaks extending a foot or more along the grain. Many layers of wood over the wound have curly grain. The blemishes are of no consequence for coarse structural work, but destroy the value of the wood for ornamental purposes (Oregon, A. M. 444). Western hemlock (Tsuga heteropTiylla).—A specimen of this wood collected at Detroit, Oreg. (H.), shows reddish to black resinous scars 1 to 3| inches long, and the wood immediately over the wound gnarled and distorted, and one or two annual rings impregnated with a black crystalline resin deposit. The smaller blemishes produced by sapsucker work are practically identical with those described by H. E. Burke as black check, which is caused "by an injury to the cambium ... by the hemlock bark maggot, Cheilosia alaskensis.'''' Mr. Burke says:'' Timber badly affected with this defect is nearly worthless for finishing, turning, staves, and wooden- ware, for which it would other- wise be excellent.''l But inju- ries l>y sapsuckers generally occur on a larger scale and consequently are more damag- Fig. 12.—Effects of sapsucker work on wood of bald jjijr Specimens of West e I'll cypress (Tatodium distichum). Checks and stains. ,'~ . .. , ,. , r t-» 1 hemlock collected by Mr. Burke at Hoquiam, Wash. (II. 2167a), show the removal by sapsuckers of long vertical strips of bark, exposing the sapwood (PL VIII, fig. 3). This weal hers to a dark color and when healed over persists as a darkly stained area from 2 to 3 inches wide and up to several feel long with more or less resin deposit, making a thin brittle layer in the wood along the plane of which splitting easily occurs (PI. VIII, fig. 5). The defect is extreme, both as to weakness and unsightliness, and when abundant and scattered throughout the wood, as sapsucker b
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