December, 1921 



BETTER FRUIT 



Page? 



Suggestions for Pruning Apple Trees 



Bi/ O. B Whipple 



Formerly Horticulturist, Montana Agritultiirid E^feritneitt Station 



IN THIS discussion on pruning I pro- 

 pose to confine myself almost entirely 

 to problems relating to the pruning of 

 the apple. I believe that some fruit 

 growers are poor pruners because they lack 

 faith in their pruning ability. Many a tree 

 goes unpruned because the owner feels that 

 there are mysteries in the art of pruning 

 of which he knows nothing and that the 

 tree is better off unpruned than wrongly 

 pruned. Too often the same grower will 

 turn his trees over to some itinerant prun- 

 ing expert, so-called, who, barring his 

 nerve, is no better qualified to do the work 

 than the owner himself. To be a good 

 pruner one must understand the principles; 

 he need be a good observer and experience 

 is of course helpful, but after all there 

 are not many mysteries involved. 



Inconsistency in pruning is another fault 

 of many pruners. I do not refer to those 

 cases where through miscalculation or lack 

 of experience the tree is allowed to become 

 too thick and must finally be severely 

 pruned to be properly thinned out. There 

 are many who just don't get around to 

 prune every year. Such spasmodic pruning 

 tends to keep the balance between growth 

 and fruitfulness more or less upset and it 

 certainly does not lessen the labor involved. 

 Moderate annual prunings will give much 

 more satisfactory results than those of the 

 spasmodic nature. Too frequently severe 

 prunings mav come at the wrong time. For 

 instance, how many times have you heard 

 the fruit grower say, "Well, I don't expect 

 a heavy crop this year as I had a big one 

 last, so I will take this opportunity to give 

 my orchard a good thinning out." 



There is no poorer time to prune the 

 orchard heavily than the spring just pre- 

 ceding the off-year. A great majority of 

 the fruit spurs bear only branch buds and 

 the severe pruning may force many of these 

 into tv\:ig growth reaching the proportions 

 of water sprouts. If the heavy pruning is 

 followed by favorable growing conditions 

 the orchards may have another off-year the 

 following season, the trees expending their 

 energy in wood growth at the expense of 

 fruit-bud formation. It is well to re- 

 member that fruit-buds for the season's 

 crop are formed in July and August of the 

 previous season. The one important con- 

 dition favoring fruit-bud formation is an 

 abundance of reserve food material. This 

 does not mean that liberal applications of 

 fertilizer will make the tree produce fruit- 

 buds and fruit. This is not reserve food 

 material and when combined with ample 

 water supply may throw the tree into such 

 rapid growth as to retard fruit-bud 

 development. This does not mean that 

 heavy pruning will increase the reserve 

 food supply of the parts remaining and in- 



duce fruiting; it Is more likely to have the 

 opposite effect. 



By reserve food material we have re- 

 ference to the elaborated food stored up in 

 the tissues of the tree, food not used im- 

 mediately in the processes of twig growth 

 and fruit development. Conditions favor- 

 ing the accumulation of this reserve food 

 are good vigorous twig leaf development 

 early in the season with conditions, favor- 

 ing only moderate growth during the sea- 

 son of fruit-bud formation in July and 

 August. We must have leaves for the leaves 

 elaborate this food and we must have new 

 shoots for these bear leaves, but any sys- 

 tem of pruning which prolongs the period 

 of rapid rgowth beyond the latter part of 

 July is opposed to fruitfulness . There can 

 be no accumulation of reserve food material 

 so long as the tree is actively engaged in 

 leaf and twig development. 



TF A HF.A\'Y pruning becomes necessary 

 -'- the proper time to admininster it is at 

 the operjing of the season when the orchard 

 promises to bear a heavy crop. But here 

 again we may blunder for promises are not 

 always fulfilled and an untimely frost 

 may remove the crop which would have 

 acted more or less as a stabilizer and we 

 are again confronted with conditions which 

 favor the production of water sprouts 

 rather than fruit-buds. We can well be 

 more consistent in our pruning. Adopt a 

 plan, follow rather a middle course, 

 modify the plan as experience dictates, but 

 don't swing from one extreme to the other. 



But we can be too consistent in our prun- 

 ing as well as inconsistent. ' Most fruit 

 growers now appreciate that to develop a 

 good framework we must prune the young 

 tree severely. As we train the young 

 orchard we unconsciously become devotees 

 of severe pruning. As the orchard reaches 

 the bearing age we hope for fruit, we even 

 pray for fruit, but we forget the principles 

 of fruit-bud formation. The only reason 

 a young tree does not bear fruit is that it 

 is expending its energies in twig growth 

 and has no reserve for fruit-bud develop- 

 ment. It grows early and late and so long 

 as we continue the practice of severe prun- 

 ing we are opposing fruitfulness. There 

 comes a time in the life of every orchard 

 when moderation must be practiced in 

 pruning. Many of our younger Montana 

 orchards are now in this stage. Once the 

 fiamework is well developed we should do 

 just as little pruning as possible until the 

 tree shows signs of over-bearing. 



Of course some pruning will be neces- 

 sary to remove branches that interfere with 

 others. But the plan should be to increase 

 rather than decrease the number of grow- 

 ing points. We can do this by heading in 



the small growth in the center of the tree 

 rather than by removing it entirely. This 

 small growth may be developed into the 

 first fruiting wood of the tree. True, 

 it may be necessar}' to remove this wood 

 later, but it serves a purpose in aiding to 

 bring about a balance between growth and 

 fruitfulness which is long delayed if we 

 continue the practice of severe pruning as 

 outlined for the orchard during its forma- 

 tive period. There is really much to be 

 gained in early fruit production if we 

 properly preserve this small wood in the 

 center of the tree. And let us not forget 

 that the first three or four years should 

 see the season of formative pruning past 

 and the inauguration of another pruning 

 program which will tend to reduce rather 

 than encourage the growth of wood. 



This period of moderate pruning may 

 extend through the next four, five, six or 

 seven years or even longer. It will depend 

 upon how well the orchard is cared for 

 in the way of irrigation, cultivation and 

 fertilization. It may even depend upon 

 the varieties planted. The passing of this 

 period of moderate pruning will be plainly 

 Indicated by a tendency for the tree to bear 

 heavy and lignt crops alternately, by an 

 undesirable decrease in the size of the fruit 

 especially during heavy fruiting seasons, 

 and by a lack of twig growth. But when 

 these signs indicate that the tree has 

 entere.d into this period of fruitfulness we 

 must not get over-anxious about pruning 

 for here is where thinning may be practical 

 with profit. It is well to maintain an 

 ample supply of fruiting wood. In the 

 first place trees so pruned will often go 

 through periods of late spring frost and 

 still bear a profitable crop, when trees 

 stripped down to the minimum of fruiting 

 wood will be thinned down seriously. We 

 have all seen Instances of where the orchard 

 neglected as to pruning will bear a better 

 crop such seasons than the orchard which 

 has received more ideal treatment in this 

 respect. 



AGAIN if we are to secure annual crops 

 we must maintain a greater number of 

 fruiting spurs than required to produce a 

 maximum crop. The fruit spurs of the 

 apple and pear and even those of the plum 

 and apricot are inclined to bear only alter- 

 nate years. Theoretically then we must 

 maintain twice the amount of fruiting 

 wood required to produc-c a good crop. We 

 must then see that not more than one-half 

 of this wood matures a crop in any one 

 season. I do not mean by this that such 

 a tree properly thinned will always bear 

 a crop of fruit. There are certain varities 

 in which alternate bearing can hardly 

 {Corttinueil on fage 21) 



