Pruning For Fruit 



By V 



Our primary object in maintaining an orchard is to take 

 from it >ear after year the largest possible quantities of 

 fruit of the best possible grades and at the lowest prac- 

 ticable costs. It is because of this that we cultivate, fer- 

 tilize, thin, spray, prune and otherwise care for the trees. 

 This being true, the value of any particular orchard op- 

 eration or practice can be — and should lie — measured by 

 the way in which it influences yield, grades and cost of 

 production. 



If then we ask the question. "Why do we prune?" our 

 .answer is that fundamentally we prune to get more fruit 

 and better fruit, to increase quantity and quality. At this 

 point it may be objected by some that we also prune to 

 secure a certain shaped tree. That, however, is a matter 

 of training, and pruning should not be confused with 

 training. Training has to do with the shaping of trees, 

 with making them assume one form or another. 



We train trees with open or close centers : with round, 

 spreading or flat tops ; with many or few scaffold limbs ; 

 with high or low heads. Training does not have to do 

 directls' with the functioning, with the behavior, of the 

 tree. .V tree trained with an open center may be much 

 better adapted to a certain soil, a certain slope and a cer- 

 tain amount of humidity than a close centered tree of 

 the same variety. The reverse may be true of the same 

 variety under an entirely difi^erent set of conditions. 



But whether in training we secure a good shape or a 

 poor one for a certain variety, under our conditions, train- 

 ing has to do primarily with form. On the other hand 

 we prune trees to so modify, to so control, their fruit 

 habits that larger and more regular cro])s of better fruit 

 will be borne. In other words, we prune to modify 

 function. 



B'roadlv speaking, we can control the fruiting habit of 

 fruit trees onl\' in so far as we can control their machinery 

 for, fruit production. The flower is usually regarded as 

 the mechanism that the plant constructs for the ultimate 

 purpose of fruit and seed formation, l)ut flower formation 

 depends, to a very large extent, upon the number of 

 flower spurs, or. as we call them, "fruit spurs," and upon 

 their behavior. 



This is practical]}' the ec|uivalent of saying that the 

 fruit spur is the real machine throusjh the operation of 

 which fruit is manufactured. Possibly excejition mav be 

 taken to this in the case of bearing on one-year-old wood, 

 but this rather extraordinary habit of some varieties of 

 apples and pears is not general enough to seriously con- 

 flict with the statements made. At anv rate, the fruit 

 spur is the mechanism that the tree usually employs in 

 its work of fruit bearing. 



WitlnnU 'doubt manv factors influence the initial de- 

 velopment and the later health and vigor and regularit\- 

 of' functioning of fruit spurs. Indeed there are eood 

 reasons to believe that most of our orchard practices, 

 such as cultivation, fertilization, spraying, the use of 

 cover crops, etc., influence them either directly or in- 

 directly. Pruning, however, has generally been looked 

 upon as a practice through which we directly influence 

 fruit spurs. All fruit growers know that thev can prune 

 them out and thus reduce their numljcr. Many believe 

 that by this or that pruning practice they can stimulate 

 their formation or possiblv increase their vigar or 

 lengthen or shorten their life, etc.: and these beliefs are 

 founded upon careful observation and experience. 



The trees in some orchards are full of fruit spurs ; 

 those of other orchards are relatively much fewer in 

 number. The individual fruit spurs in some orchards 



R. Gardner. 



average an apple or a pear once every two or three years ; 

 those in other orchards average a fruit only once in four 

 or five or six or eight or even ten years. The average 

 length of life of the fruit spur in some trees may be three 

 or four vears ; in others thirty or forty years. These are 

 e.xtremes, of course, but they represent facts regarding 

 the fruit manufacturing machinery in our orchards. 



The health, vigor and longevity of the fruit spur de- 

 pend upon its food and moisture supply and upon the 

 amount of sunlight that it receives. It is possible for a 

 tree to be so situated that there is not enough moisture 

 and food present to supply properly all the spurs and 

 their developing fruits. It is also possible for the upper 

 and outer limbs to be so numerous and the growth they 

 make so dense that many of the inner and lower branches, 

 with their fruit spurs, receive insufficient light to keep 

 them thrifty. Later these shaded spurs die oif and the 

 fruiting area of the tree is thereby reduced. 



L'nder these circumstances judicious pruning would so 

 limit the number of spurs that there would be food and 

 moisture for all; and the branches would be so thinned 

 that enough sunlight would filter through the outer and 

 upper part of the tree to keep the remaining parts grow- 

 ing vigorously. 



Though possibly a smaller percentage of fruit grow- 

 ers under-prune than over-jirune, too little pruning is 

 without question the direct cause of small crops and in- 

 ferior fruit in many orchards. It is not necessary to visit 

 a large number of orchards in order to find evidence of 

 too light pruning. Dead and dying fruit spurs are very 

 common, especially on older trees. There may be loss 

 of fruit spurs from dense shading in over-pruned trees, 

 and there will, of course, be a certain loss from other 

 perfectly legitimate causes such as occasional injuries in- 

 cident to picking in very well-cared-for trees, but in gen- 

 eral the dving out of many fruit spurs indicates too 

 little pruning. 



The practical question at once arises: "How much are 

 We to prune?" From the very nature of the question no 

 answer can be given which can be taken as a rule to be al- 

 wavs followed. It is the principles which underlie tree 

 growth and fruit production that determine amount of 

 pruning. ( )nly as these principles are applied to each in- 

 dividual problem as it arises — in other words, to each in- 

 dividual tree — can the right amount of [iruning be done. 

 From what has been said it is evident that jjroper ]iruning 

 consists in the removal of just enough wood to afford 

 the largest possible number of fruit spurs a good supply 

 of light and food, and consequently keep them growing 

 vigorously and fruiting regularly. A tendency on the 

 part of the tree to produce water sprouts and other wood 

 growth at the expense of fruit spurs indicates that two 

 iieavv pruning has already been done. Irregular bearing 

 and dving out of fruit spurs indicates that too little prun- 

 ing or pruning in the wrong part of the tree, or both, have 

 been faults of recent years. The person who prunes 

 should glance quickly over the tree, judge quickly and ac- 

 curately of the balance (or lack of it) that exists between 

 wood and fruit production, between vegetative growth 

 and fruit-bearing surface, and then proceed to restore or 

 maintain this balance. In its last analysis the question of 

 amount of pruning becomes a question of judgment. 

 Rules cannot be given, or if given they are almost worse 

 than useless. They mislead as often, or more often, than 

 they lead aright. Principles governing amount can be 

 more or less thoroughly understood and then applied to 

 individual cases. Principles are always the same. 



