INSECT INJURIES TO HARDWOOD FOREST TREES. 



827 



broken, decayed, and worthless trunks. The great number of "stag- 

 horn " tops of the older oak trees in our forests everywhere give evi- 

 dence of the destructive work of this class of heartwood borers. 



METHODS OF CONTROL. 



The only method we have to suggest for combating this insect is to 

 fell and utilize all matured timber that shows the slightest indication 

 of diseased conditions of the top, and clean up and burn such parts as 

 show evidence of being infested. 



WORK OF THE COLUMBIAN TIMBER-BEETLE. 



One of the commonest wormhole defects in white oak, rock oak, 

 beech, and tulip (" whitewood" or " yellow poplar") is one known to, 

 the lumber trade as grease 

 spots, patch-worm, or black 

 holes (fig, 38), steamboats 

 (tig. 39), etc., caused by the 

 Columbian timber -bee tie 

 ( ( 'ortkylw Columbian us 

 Hopk.). 



CHARACTER OF THE WORK. 



The characteristic features 

 of the wormhole defect, 

 which will enable it to be 

 readily recognized in oak 

 and beech, are transverse 

 MM-ies of two or more black 

 holes about the size of the 



lead in an ordinary lead pen- FlG - 41 -~ Work of Columbian timber-beetle: End of log, 



i " 4. . -, showing evidence of serious damage, and how the 



reak Ot Stained brood galleries made in the sapwood are covered by 



WOod extending with the subsequent growths of wood. (Adapted from author's 



_. illustration.) 



gram 2 or 3 or more inches 



each side (as in fig. 38). In quarter-sawed oak or split or sawed 

 staves, a short longitudinal section of one of these black holes is seen 

 attended by the stained streak on one side of a thick or curly growth 

 or grain (fig. 39). It is this form which is called steamboats. In 

 whitewood or yellow poplar the black holes are attended by very long 

 black, greenish, or bluish streaks, sometimes 5 or 6 feet long. When 

 this is common in the lumber it is called calico poplar. Fig. 40 rep- 

 resents the characteristic appearance of this defect greatly reduced. 

 The appearance of the defect in the end of a log is represented in 

 fig. 41, and in the sapwood of a living tree in fig. 42. 



