GROWING AND FRUITING HABITS 391 



means of modifying shape and in more detail as it influences development, 

 location and functioning of the fruiting machinerj^ of the tree. 



PRUNING FOR FORM— TRAINING 



There is frequent failure to distinguish clearly between pruning and 

 training. The two practices are often regarded as one and the same or 

 at least as inseparable. Training concerns form primarily; pruning 

 affects function primarily. Training determines the general character 

 and even the details of the plant's outline and of its branching and frame- 

 work; pruning is meant to assist more in determining what the tree 

 does in respect to fruiting. Training may be illustrated by reference 

 to what may be done easily with the grape. Without cutting off or 

 cutting back a single cane, it is possible to train a vine on a one-wire 

 trellis, a two-wire trellis, a three-wire vertical trellis, a three-wire hori- 

 zontal trellis, an arbor, or in any one of a dozen other ways. The 

 training simply gives the vine its form and has comparatively little to 

 do with the number or size of the bunches of fruit it produces. Similarly, 

 fruit trees are made to assume one form or another — for example, high- 

 headed or low-headed, open-centered or closed-centered, flat-topped or 

 pyramidal — and production is influenced comparatively little by these 

 shapes. It is true that the pruning saw and shears are generally used in 

 forcing the trees into the one shape or the other, and hence, perhaps the 

 operation should be spoken of as "pruning for form." Nevertheless 

 the operation affects form principally and consequently is here discussed 

 under the heading of training, even though strictly speaking the use of 

 that term should be limited to such changes in form as are effected with- 

 out the removal of parts. If parts are removed at such a time and in 

 such a way as to modify materially the functioning of the whole tree or of 

 some of its parts, even though its general shape is left unchanged, the 

 operation should be considered pruning. Many times both shape and 

 function are modified by a single operation, which then is to be regarded 

 as both pruning and training; often, however, it is chiefly one feature of 

 the tree's growth that is influenced. 



General Objects. — In general, training has little direct effect on 

 the amount of fruit borne. Some of the pruning practices that accom- 

 pany certain methods of training may affect yields profoundly, but the 

 training in itself is of only secondary importance in this connection. On 

 the other hand training may be a factor in determining grade, or what 

 is frequently referred to as " quality. " Its influence on grade is produced 

 largely through making it difficult or easy to spray thoroughly and 

 consequently in aiding or hindering the control of insects and diseases. 

 Standard control measures for certain pests may lose half of their effi- 

 ciency if the plants have been untrained or poorly trained. This influ- 

 ence is distinct from and additional to the direct control of certain pests 



