CHAPTER VI 



INJURIOUS INFLUENCES FROM SOIL OR 

 ATMOSPHERE 



DISEASES due to an unsuitable condition of soil 

 and situation are most noticeable in stagheaded 

 trees and in such as are subjected to atmo- 

 spheric impurities or to excessive drought or 

 dampness. 



Stagheaded trees, or such as have the top 

 branches dead and dying, are common enough 

 in the case of old specimens or such as are 

 growing under unfavourable conditions as to 

 the amount of dampness in the soil. But 

 many causes may bring about the death of the 

 crown of a tree, such as lowering the water 

 level by the making of a lake or by excessive 

 drainage, exposure of the trees to chemical or 

 other fumes, and, in the case of old park trees, 

 by exhaustion of the soil and want of nourish- 



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