392 FUNDAMENTALS OF FRUIT PRODUCTION 



by cutting out and destroying infected parts. In certain fruits the 

 shape and openness of the tree is important in influencing the colora- 

 tion. Training is important also in reducing certain production costs. 

 Tillage and other soil treatments, spraying, thinning, propping, trellising 

 and harvesting all may be greatly facilitated by proper training. 



In a general way training should tend so to distribute the fruiting 

 wood and the fruit that all orchard or vineyard operations may be con- 

 ducted with greatest facility and lowest cost. It should eliminate or 

 minimize the necessity and cost of trellising, propping, or artificially 

 supporting the plant and its fruit. It should provide the leaves and 

 developing fruits with as nearly as possible optimum conditions for 

 coloration without danger from sunscald and, wherever feasible, it 

 should aim to provide those conditions least favorable for the work of 

 injurious insects and diseases. In view of all these possible effects of 

 training and of the widely varying conditions under which plants of even 

 the same variety are grown, it is evident that the best method of training 

 a plant in one situation may be quite distinct from what is best in 

 another and it often happens that two fruits or two varieties of the same 

 fruit should be trained differently when grown in the same environment. 



Since the training of trees presents certain problems quite distinct 

 from those of pruning it seems desirable to consider them separately 

 from their possible influence on function. 



Details in Training. — A comparatively large part of the training 

 that trees are to receive should be given during the first few years of 

 their growth. It is during this period that they are building their frame- 

 work and taking on the general form that the grower has decided shall 

 be theirs during the rest of their lives. During later years efforts are 

 directed mainly to preserve the form already given the tree and attention 

 is given to its pruning as distinguished from training. 



Height of Head. — By height of head is meant the distance from the 

 ground at which the main or scaffold limbs branch from the trunk. 

 Trees in which the scaffold limbs come out within 23^^ or 3 feet from the 

 ground are spoken of as low-headed; those in which they come out from 

 the trunk 4 feet or more from the ground are high-headed. The height 

 of head generally is established at the time of setting by the distance 

 from the ground at which the top is cut off though it is possible to raise 

 the head or sometimes to lower it by later treatment. In the older 

 orchards high-headed trees are the rule. It was thought that high- 

 heading facihtated cultivation and other orchard operations and perhaps 

 was better for the tree. More recent tendencies have been in the 

 direction of lower heads. If properly handled it is no more difficult to 

 cultivate around and under such trees and pruning, spraying, thinning 

 and picking are greatly facilitated. Furthermore, low-headed trees are 

 less subject to sunscald and suffer less from high winds. 



