ruyr gkneral principles. 



whole. We prune to induce fruitfulness, and to diminish 

 it. We prune in the growing as well as in the dormant 

 season, and, finally, we |)rune both roots and branches. 

 Thus we see that pruning is applied to all parts of the 

 tree, at all seasons, and to produce the most opposite 

 results. 



It appears necessary to ti-eat of pruning, under each of ^ 

 these circumstances, separately. 



1st. Priminr/ to dlrct the Growth from one part of 

 a tree to another. — The first period in the existence and 

 growth of a tree in which this becomes necessary, is in 

 the nursery. Those who have liad any experience in tree 

 culnire, have ohserved that young trees in nursery rows 

 ha^^e a tendency to increase in lieight without acquiring a 

 well-proportioned increase in diameter. In certain cases, 

 this* want of proportion becomes so great, tliat the tree 

 bends under its own weight, and hence it is necessary to 

 res'-rt to some method of propping it up. This condition 

 is attributable to several causes. First, the absence of a 

 sufficient amount of air and light around the stem, to 

 enable the leaves on it to fulfill their functions properly. 

 It has been shown that the formation of new wood de- 

 pev«ds upon the elaborating process carried on in the 

 leaves, and that this process can be maintained only in a 

 free exposure to the sun and air. This being the case, it 

 is obvious that any ]iart of the tree excluded from the 

 action of these agents caimot keep pace in growth with 

 other parts to which tliey have full access. In nursery 

 rows, as trees are usually planted, the stems, after the 

 first year's growth, are to a ureat extent excluded from 

 the light, consequently the buds and leaves on tliem can- 

 not perform their ]iarts in the creation of new wood. The 

 top of the tree, however, is fully exposed, and, conse- 

 quently, it makes a rapid growth towai-ds the free air and 

 light. When this is continued for two or three years in 

 succession, the tree becomes top-heavy; the quantity of 



