GROWING AND FRUITING HABITS 407 



attained either through modifying the form or through influencing the 

 functioning of the tree as a whole or of its individual parts. Pruning 

 for form is essentially training. Training seeks directly to secure the 

 distribution of the fruit bearing parts that is most advantageous for 

 economy of production, disease and insect control, for minimum loss 

 from breaking of limbs and for proper coloration. These ends are fur- 

 thered by (1) heading the tree properly, (2) providing a reasonable 

 number of well-spaced scaffold limbs, (3) preventing the formation of 

 weak crotches, and (4) keeping the tops of the trees from growing too 

 high or spreading too far. Pursuant to these aims the plants are generally 

 trained in one or another of several' standard shapes. Thus training 

 results in a certain degree of uniformity of appearance in the orchard. 

 The bearing habits of most species and varieties are fairly well fixed, 

 though they are subject to some modification by pruning and other 

 cultural treatment. Fruit buds are differentiated either terminally or 

 laterally and when they open they may give rise to (1) leafless flower 

 clusters, (2) leafy growths with terminal flower clusters, or (3) leafy 

 growths with lateral flower clusters. There are thus six distinct bearing 

 habits and in addition a number of combinations between these types. 

 The more common fruits are classified in respect to their bearing habits. 

 Alternate bearing is not a necessary product of any type of bearing. If 

 nutritive conditions within the tree are favorable fruit buds may be 

 formed every year. Consequently alternate bearing is a problem in 

 nutrition. Different bearing habits are probably associated with differ- 

 ent methods or places of food storage. 



