462 Repoet of the Depabtment of Horticulture of the 



store up greater quantities of reserve food than they otherwise 

 could. This summer heading-in should be done before growth 

 ceases. So much, however, depends upon several varying factors 

 that no fixed rule can be given as to time; thus, much depends 

 upon the fruit, the varieties, soil, climate, weather and the amount 

 of growth. 



Summer pruning is a weakening process and may permanently 

 injure a tree in our climate. With standard trees it is only of 

 advantage in moderation in eastern North America and as usually 

 practiced more often results in evil than in good. Summer prun- 

 ing is of more value in the early life of the tree than later on. 

 Summer pruning as means of inducing fruitfulness is greatly 

 overestimated under American conditions and belongs more 

 properly to the elaborate systems of pruning and training prac- 

 ticed by Europeans. 



Those who do not find pruning a sufficiently drastic method of 

 checking wood growth to augment fruitfulness, may resort to the 

 removal of a ring of bark from the trunk of the tree. In rather 

 extensive experience on the grounds of this Station, we have 

 found ringing of some use with the apple. Our practice is to 

 remove a ring of bark from one-half to one inch wide from young 

 apple trees at the period when the trees are making the greatest 

 growth, usually about the middle of June. If the ringing is done 

 earlier in the season or later in the season than June, injury is 

 certain to result. Should it be done when the growth is being 

 checked by drought, injury would also result. 



The theory upon which ringing is based is simple. Crude sap 

 passes from the roots to the leaves through the outer layer of wood. 

 In the leaves this crude material is acted upon by various agencies 

 and transformed into food substances. This accumulated material 

 passes downward through the inner bark to be distributed through- 

 out the plant where needed. When trees are ringed the flow of 

 sap upward through the wood continues as before the operation 

 but the newly made food-substance can not pass below the girdle 

 and, therefore, accumulates above and is used for the formation 

 of fruit buds though at the expense of other parts of the plant 



Is heredity a factor in bud formation '. Can the fruit-bearing 

 habit be passed down from one tree generation to another \ Can 

 the habit be augmented and intensified by selection ? Individuals 

 in an orchard vary as to time of coming into bearing, regularity 

 of bearing and number of buds formed in any season. But it has 

 not been proved that buds chosen from the trees best in these 



