362 HORTICULTURE. 



be trimmed rather than the branches, although no root 

 should be removed unless it is mutilated. If young trees, 

 when transplanted, are trimmed at all, it should be done in 

 the fall, when the quantity of nutrition laid up in them ena- 

 bles them to sustain such losses as they must suffer in the 

 process. 



Root-pruning, however, may be advantageous to trees 

 which produce leaves rather than fruit ; and some gardeners 

 have thus rendered their trees fruitful. 



There is a peculiar kind of pruning, called ringing, that is, 

 the removing of a ring of bark, at certain seasons, for the pur- 

 pose of stopping the sap as it descends from the leaves, and of 

 turning it either to the formation of fruit-buds or fruit, as the 

 season may be. This operation, however, although it often 

 increases the quantity and quality of the fruit, endangers the 

 /life of the tree, and is rarely resorted to. The same effect is 

 sometimes produced by placing a heavy stone in the fork of 

 the limbs. By the pressure it exerts, and by the compression 

 it gives to the limb, it obstructs the free circulation of sap, 

 and thus increases the quantity of fruit.* 



II. Training is an operation wholly artificial. It has for 

 its object the placing of a plant in a position different from 

 what it could ever attain of itself, in order to gain the advan- 

 tage of light, heat and support. Hence plants are generally 

 trained or made to grow by a south wall, where the tempera- 

 ture is more equable, and where the winds are shut off so 

 that perspiration or evaporation (a frequent cause of injury) 

 is more equal and moderate. 



1. By thus exposing a tree to a warmer atmosphere, the 

 sweetness of the fruit is nmch increased ; hence plums, 

 pears and grapes are much sweeter grown on walls with a 

 southern exposure. 



2. By training, the circulation may be impeded, and the 



* Lindk>v. 



