88 TREE WOUNDS AND DISEASES 



the soil and hastens the death of trees within 

 its area. 



The effect of gas on trees is somewhat 

 curious : sometimes they die off quickly, ap- 

 parently without the slightest warning ; and at 

 other times the leaves look sear and thin, the 

 bark peels off, and gradually the branches give 

 way, until finally the whole tree succumbs. 

 This may be accounted for by the quality of 

 soil and amount of gas leakage, for when all 

 the roots are in the affected area the death of 

 the tree is rapid. 



Many instances have lately occurred in the 

 Metropolitan area in which trees have either 

 been killed outright, or become so unhealthy 

 that their removal was imperative, by an 

 escape of gas, notable examples being at 

 Holloway, Hampstead, and the Garden City 

 at Letchworth. 



Shedding of the bark, especially in town 

 trees, is an early indication that most probably 

 the tree so affected is being gradually poisoned 

 by an escape of gas. Small patches, at first 

 near ground level, fall off, but as time wears 

 on large breadths become affected, the tree 



