20 THE WESTERN HEMLOCK. 



The danger is lessened by thick bark, which renders it difficult for the 

 insects to enter. For the same reason large trees are safer than small 

 ones. They are frequently streaked near the center, but not toward 

 the outside, showing that when the tree reached a certain size its bark 

 became thick enough to protect it. (PI. VII, tig. 1.) As yet protec- 

 tive measures against this insect are unknown, but much disappoint- 

 ment might be prevented by an examination of standing timber for 

 traces of the insects. It is useless for manufacturers of cooper stock 

 or finishing lumber to buy infected logs. The presence of the larva 

 in the standing tree is always apparent to a close observer. 



IMMUNITY FROM WHITE ANTS (TERMITES). 



Experiments made in Manila indicate that Hemlock ma3 T prove of 

 special value in tropical countries where most woods are destroyed bj T 

 ants. Capt. George P. Ahern, chief of the Philippine forestry bureau, 

 states in a recent report that the master mechanic of the depot quarter- 

 master's shops, Mr. D. N. McChesney, tested several American woods 

 by thirty days 1 exposure to the attack of ants with the following 

 results : 



Oregon Pine (Red Fir) Entered and eaten; a mere matter of time for complete 



destruction. 



"I Eaten more readily than Oregon Pine. 



Spruce . . j j ^ 



California Redwood -> . , ,. . , 



^ ^•e w , •, ri j > . - Ants tried, out discontinued after slight effort. 



California \\ lute Cedar / e 



Hemlock Not touched. 



Further experiment is now being made. Since the depredations of 

 ants are of great importance, not only in the Philippines but in other 

 tropical countries, a wood which will withstand them is certain of a 

 good market. Although Cedar and Redwood have the reputation 

 of being ant proof, they are not adapted to many uses for which 

 Hemlock is excellent. 



For many years farmers have used Hemlock for the construction of 

 oat bins and similar receptacles designed to be rat and mouse proof. 

 It is said that the wood is distasteful to all rodents. 



PARASITES. 



A parasite {Arceuthobium occldentale) resembling mistletoe is wide- 

 spread throughout the Hemlock region. It grows upon the branches 

 and leading shoots, causing distortions and occasionally death. When 

 the branches only are attacked, the result is a disturbance of their 

 functions, and consequently a slow, sickly growth of the tree, which, 

 however, does not affect the quality of the timber. If, however, the 

 plant gets foothold on the leading shoot, a burl follows which persists 



