452 FUNDAMENTALS OF FRUIT PRODUCTION 



portion, but that part which is defoliated functions as it would if all the leaves 

 had been removed from the whole tree. 



"Removing the same number of leaves, without any pruning, has practically 

 the same effect upon the fruit-bud formation for the immediate year following 

 that a summer pruning, removing leaves from the same position, would have. 



"Buds on 1-year wood, in areas from which the leaves have been removed 

 are slower in starting out into growth, and make a weaker growth the following 

 spring than do other buds on the same shoots not defoliated. This is more 

 noticeable in some varieties than in others. 



"One shoot seems to be very largely independent of other shoots about it so 

 far as fruit-bud formation is concerned. It is apparently largely dependent upon 

 its own leaves for nourishment. 



"Removing leaves from individual spurs tends to prevent the formation of 

 fruit buds upon those spurs, although it does not entirely check the development 

 of flower parts. 



"On those spurs which form fruit buds, notwithstanding defoliation, the 

 blossoms are, on the average, considerably later in opening in the spring. 



"Axillary buds of the Wagener seem to be almost entirely dependent upon 

 the immediate subtending leaf for the carbohydrate supply with which they are 

 nourished. Removing the subtending leaf entirely prevents fruit-bud formation. 

 Buds so treated either remained entirely dormant during the following growing 

 season or pushed out into very weak growth. Very few of them showed a 

 development approaching normal." 



Magness' work may explain incidentally why the basal portions of 

 shoots often produce relatively fewer fruit buds than the median and 

 terminal portions. The basal portions are poorly lighted and, assuming 

 leaves of equal size, they would manufacture smaller amounts of elabo- 

 rated foods. Neither spurs nor shoots can be expected to differentiate 

 fruit buds freely if they are heavily shaded. Summer pruning, however, 

 naay admit more light both to the spurs and to the basal portions of 

 the shoots at the same time it concentrates the supply of nutrients. 

 This direct influence on the factors associated with fruit-bud formation 

 could hardly help but influence more or less directly the relative number 

 of fruit buds. Obviously early summer pruning comprising thinning 

 out instead of heading back would have the greatest influence of this 

 kind. No pruning practice after fruit-bud formation for the season 

 is completed could conceivably have any influence in this direction and 

 heading back with the formation of many secondary lateral branches 

 would cause still heavier shading and reduce rather than increase fruit- 

 bud formation. Doubtless many of the cases in which summer pruning 

 has failed to produce an increased number of fruit buds have been due 

 to its consisting mainly in heading back or being done too late to 

 have any important influence in this direction. Experience shows that 

 a light or moderate early summer thinning of the shoots of those trees 

 such as the peach that bear laterally on shoots aids greatly in the forma- 



