GBOWING AND FRUITING HABITS 395 



Lowering the Tops of Trees. — In the course of time the trees of many 

 species become so tall that the added cost of gathering the fruit from the 

 topmost branches reduces the margin of profit to the vanishing point. 

 Furthermore the higher branches shade the lower and reduce their effi- 

 ciency as fruit producers. The increased difficulty in controlling insects 

 and diseases in the tops of very tall trees, even with the aid of the best of 

 the present power spraying outfits, makes those portions of doubtful 

 value to the grower even though it should be possible to harvest the 

 fruit economically. One investigator sets 25 feet as about the limit 

 in height for profitable apple production '^ ^nd with the smaller spraying 

 outfits the limit is probably well below that figure. The problem of 

 controlling the height of trees and keeping their lower branches actively 

 producing a good grade of fruit is thus very real. 



Many growers wait until the trees get much too tall for profit and then 

 "dehorn;" that is, they cut back the limbs severely, leaving large stubs 

 that promptly send out an abundance of strong vigorous watersprouts. 

 Eventually new fruiting wood is developed from this new growth, but in 

 the meantime crowding is likely to force this new growth up, so that by 

 the time the top has been bearing a few years it is too high again and 

 another dehorning becomes necessary. 



A much better method of lowering the tops of tall trees is to cut back 

 into 2-, 3-, or 4-year-old wood, always to a lateral branch. The more 

 nearly horizontal this side limb, the better. By thus cutting to a lateral 

 the flow of sap is utilized in a somewhat increased growth and few or no 

 watersprouts develop. A year or two later this lateral can be cut back 

 to one of its side branches, or perhaps the whole structure can be removed, 

 the cut being to a still lower side limb on the main branch that in the mean- 

 time has been strengthened by the heading back of the season before. 



This, it will be recognized, is a procedure aiming constantly to keep 

 the tree within bounds rather than permitting it first to become far too 

 tall and then greatly reducing its height. To be most successful it 

 should begin when the tree reaches about the desired height and from 

 then on it should constitute a part of the regular annual treatment that 

 the tree receives. It will not be necessary to lower every part or limb 

 of every tree each year; only the tallest, those getting too high, need be 

 cut back. This practice not onlj^ results in the production of fewer 

 watersprouts but it keeps the lower part of the tree in a better producing 

 condition than is possible with occasional dehorning. It is a heading 

 back in name mainly — really resulting in more thinning than cutting 

 back — and is followed by the kind of a response that attends thinning 

 out. 



Eliminating and Subordinating Limbs. — It has just been stated that 

 in the training of open-centered trees it is usually better to suppress or 

 subordinate the interior limbs than to attempt their total elimination. 



