INJURIOUS INFLUENCES 89 



wears a decidedly unhealthy, sparsely foliaged 

 appearance, and finally dies off. As if to 

 hasten the decay of an injured tree, the elm 

 bark beetle and the goat moth quickly appear 

 on the scene and tunnel the already diseased 

 wood and bark, thus aiding the poisonous gas 

 in its work of destruction. In some instances, 

 where the cause was discovered at an early 

 period, good results have been brought about 

 by remedying the evil ; but usually the location 

 of a leakage is by no means easy, as in loose 

 soil the escaping gas will follow the pipe for 

 several yards. 



Soil that once has become tainted with 

 escaping gas rarely regains its original sweet- 

 ness, and is unsuitable for the healthy develop- 

 ment of plant life ; and so it is that, when once 

 affected, few trees permanently recover. Fresh 

 lime thoroughly incorporated with the soil is 

 perhaps the best remedy for gas-infested areas. 



From this it will be inferred that an escape 

 of gas near the roots of a tree has a most 

 injurious effect and is difficult to contend 

 with, for, once the soil is poisoned, a return 

 to normal condition is rarely brought about. 



