EXPERIMENT STATION BULLETINS. - 395 



few long, straight branches, rather than a more compact head. The problem, 

 then, is to induce more rebranching and more growth. Heading back to the 

 base of one-year-old wood, or sometimes in two- or three-year-old wood, is 

 advisable. This treatment should be supplemented with such cultural prac- 

 tices and fertilizer treatment as will better growth conditions. 



Thus, the treatment for sweet cherries is light compared to that for apples 

 and peaches, and it differs in kind in that more thinning-out is necessary for 

 young trees and more heading back for old trees. 



Sour Cherries — The modified leader type of tree seems to be preferred by 

 commercial sour cherry growers. Generally speaking, the young sour cherry 

 may be trained as the apple, except that more scaffold branches, four or five, 

 should be left each year and the leader suppressed after two or possibly three 

 seasons of growth. A greater number of scaffold branches are desirable for sour 

 cherries than for other fruits, because of the branching habits. The j'^oung 

 sour cherry will require little or no tipping back, as it has a habit of freely 

 producing lateral branches without heading back. Even the thinning is very 

 light during this period, it being confined mostly to a removal of the larger 

 branches, other than main or scaffold ones, during the first two years. 



After the general framework of the tree is established, the pruning is mainly 

 limited to a removal of weak and dead twigs; thinning out sufficiently to keep 

 up a good supply of functioning wood throughout the tree, and heading back 

 occasional branches in the top to prevent the trees from becoming too high. 



Normally, the sour cherry bears its fruit laterally on long growths and on 

 short growths or spurs similar to those of the sweet cherry. Thus its fruiting 

 habit is intermediate between that of the peach and sweet cherry. However, 

 there is a great tendency, in Michigan, for cherry trees to produce fruit al- 

 most entirely from the lateral buds of the longer growths. In other words, 

 few spurs develop to maintain fruiting in the two-year-old and older portions 

 of the tree; consequently the trees have a tendency to confine fruit production 

 to the outer parts of the tree, and long branches devoid of both fruit and 

 foliage are the rule back of the one-3^ear-old wood. A careful examination of 

 trees making a short annual growth will show that practically all of the 

 lateral buds on the previous season's growth produce blossoms and later 

 fruits. Consequently there is httle opportunity for lateral twig and spur 

 development. The general tendency of trees with fruiting habits similar to 

 the sour cherry is to produce lateral fruit buds near the tip of shoots of the 

 current season's growth and lateral leaf buds which later develop into lateral 

 branches or spurs near the base of these shoots. However, if the annual twig 

 growth is short, there is a tendency for the lateral fruit buds to develop all the 

 way along the growth, and leaf buds (to form spurs and lateral growths) are 

 not produced. Thus it seems that any treatment that will induce longer 

 growths is desirable. Nitrogenous fertilizers and better cultural practices will 

 lead to quicker and better results than cutting-back to induce growth. 



