246 



THE MONTHLY BULLETIN. 

 RESISTANCE TO INJURY. 



It is a well known fact that trees vary in their susceptibility to injury 

 by the various fungous and bacterial diseases and insect pests that 



Fig. 50. — Individual resistance to fumes attaclc illustrated by oak tree. 



(Original.) 



attack them, and it is not strange to note that the same thing holds true 

 of smelter fumes injury. Figs. 50 and 51 are striking examples of this 

 fact. The large oak tree shown in the first figure has withstood the 



Fig. 51. — Individual re.sistance to fumes attack illustrated by manzanita bu.sh. 



(Original.) 



