Principles and PraElice of Pruning. 79 



branches. A part must therefore be cut off to restore the balance, 

 corresponding in some degree with the loss of the roots. This may 



Fig- 95- Nursery rows roots extending under tJte whole surface, 



be done by thinning out all the feeble shoots, so as to leave an even, 

 well shaped head, and then cutting back a part of each remaining 

 one-year shoot (Fig. 96). Judgment must be exercised as to the 

 amount to be cut away from the tops. The growth of new roots 

 depends on the assistance afforded by the leaves at the 

 top ; if the leaves are too few, the roots will not ex- 

 tend freely ; if they are too many, the roots cannot 

 furnish proper supply for them, and they will be feeble 

 and sickly. Planters will learn a great deal on this 

 point by cutting away more or less on different trees, 

 and observing the result. Different kinds of trees re- 

 quire varying management in this respecl;. The peach, 

 for example, readily reproduces new shoots, and it may, 

 consequently, be cut back very freely ; two-thirds to 

 nine-tenths of each previous season's shoot may be 

 removed without detriment. The grape, also, may be 

 very heavily pruned, as it throws out new vines with 

 great vigor. The cherry, on the contrary, is very sen- 

 sitive, and young trees have been nearly killed by a 

 severe summer pruning. The young cherry shoots 

 should never be cut back in spring more than half ed-backyoung 

 their length. The pear and apple are intermediate, 

 and the heads should be moderately and not severely pruned. 



The mutual relation between the roots and leaves has been already 

 alluded to. The leaves cannot exist without the moisture received 

 through the roots ; and the roots cannot grow without the nourish- 



