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 

 blemishes usually are, must render the wood valueless for all struc- 

 tural purposes. Besides the direct injuries to western hemlock by 

 sapsuckers, their pecks in the bark furnish entrance to bark maggots. 

 Ball cypress (Tanodiwm distichum). — Specimens from Boardman, 

 N. C. (II.), show dark stains produced by sapsucker wounds in cypress 

 and distortion of the grain in several annual rings, some of which give 

 a bird's-eye appearance in tangential section. Pieces of cypress from 

 Cottonport, La., have numerous black stains (fig. 12) from one-fourth 

 to ~\] inches in length and often nearly contiguous. In some cases the 

 holes drilled by the sapsuckers have not healed readily and have left 



' Bureau of Entomology, Circular No. 61, p. I, 1906. 



