90 TREE WOUNDS AND DISEASES 



First the foliage of the affected tree looks thin 

 and sickly, then the bark peels off, then comes 

 the attack of insects and fungi, and finally 

 what was once a strong, healthy tree succumbs 

 to the poisonous effects of escaping gas. 



The accompanying section of a town street 

 will give some idea of the difficulties trees 

 have to encounter when planted in urban and 

 suburban districts. 



