Ch. IV, 13] ECONOMICS OF STEMS 207 



If pruning is done in winter or early spring, the injuries heal 

 largely before the first rush of the valuable sap. 



There are four principal uses of pruning. First, parts 

 affected with disease which might spread to sound parts 

 can be removed. Second, some desired shape can be given 

 ornamental or fruit trees by removing growth in undesired 

 directions. This practice merges over imperceptibly into 

 the clipping of plants forcibly to desired shapes, as practiced 

 with hedges or with evergreen plants in the topiary work 

 of formal gardens. Third, more space and light can be 

 insured to a few branches, in place of a mediocre exposure 

 to many, thus promoting the development of fine individual 

 flowers or fruits. Trees and shrubs not only form many 

 more buds than ever develop, but develop many more 

 branches than is good for them all. By a form of pruning, 

 viz. disbudding, it is possible to develop the wonderful great 

 exhibition types of Chrysanthemum. 



The fourth use of pruning is the most important of all, 

 especially in orchards, — viz. to produce more formation 

 of fruit and less of leaf and stem. The possibility of gaining 

 this end by pruning depends on the fact that in plants (as 

 also in animals) a certain reciprocal balance exists between 

 the reproductive and the vegetative parts, such that any 

 check to either promotes the other, — and the fruit, of course, 

 is a part of the plant's reproductive mechanism. In a state 

 of nature, all woody plants form only enough reproductive 

 parts for their needs, and, as a phase of their competition 

 with one another for light and space, throw the remainder 

 of their energy into growth of stem and leaf. The human 

 fruit-grower, however, does not so much wish his trees to 

 become big as to bear plenty of fruit ; and by pruning 

 away much stem and leaf, he can turn the plant's energy 

 into more copious formation of fruit. Thus the cultivated 

 Grape Vines, left to themselves, produce long leafy canes 

 bearing few clusters of Grapes ; but when thoroughly pruned, 

 they produce httle cane but many fine clusters. Of course 



