PT. IV. 



PRUNING AND THINNING. 



227 



growth whatever should be allowed : roots are the 

 great creators of leaks. Nor should they be allowed 

 on masonry. Eoots, by turgescence, will rend apart 

 the strongest masonry, or lift any weight of stone. In 

 Greece, Italy, and throughout the East, roots are the 

 great dilapidators of the ruins of antiquity. We may 

 observe the effect of a too sudden exposure to the op- 

 posite force of drought in the warping and rending 

 asunder of the strongest woody organisations. 



