92 BUTLER: ALTERNATE BEARING IN THE APPLE 
developed on one-year-old wood by defoliation, cutting back,* or 
cutting into the wood above the eyes as is done when lifting a bud. 
These several methods, dissimilar as they may appear, all 
cause increase in sap pressure and not an increase in stored starch, 
' behind the buds which thereupon grow into short spurs with apical 
flower buds. The difference in starch content between fruitful 
spurs and barren spurs is an effect of the mode of vegetation, not 
the cause of it. An inspection of fruit spurs will show that those 
bearing flower buds have more leaves per unit length than those 
bearing leaf buds and consequently should contain more starch. 
But if the theory that alternate bearing is due to exhaustion 
has little or no foundation, the remedies that have been proposed 
to overcome the debilitating effect of fruitfulness are not for the 
most part without value. 
According to Beach ‘‘systematic thinning of fruit combined 
with skillful care in other directions, may. materially strengthen © 
the tendency of the tree to bear annually”’t a statement which 
can not be considered a strong endorsement of the value of thinning 
for the purpose of equalizing crop production; and effectively a 
year later we find the same author concluding as a result of 
experiments on thinning carried out for several successive years 
that ‘‘thinning the fruit did not appear to cause any material 
change in either the amount or regularity of fruit production,’’§ 
a view that must be considered substantially correct as we shall see. 
Thinning the fruit can not be expected to effectively regularize 
bearing for the reason that this operation can have but the 
following effects upon the tree: 
Ist, Thinned trees produce ceteris paribus more new growth than 
non-thinned trees; 2d, The sap drawn into the spurs to main- 
tain the fruit, is diverted after thinning into the eyes of the purse 
which develop more fully than they otherwise would have done. 
The increased growth produced by thinning will, in the normal 
course of events, flower only in the third year after the thinning was 
effected, in other words, the growth produced as a result of thinning 
will become productive a year later than the spurs that were 
* Van Tieghem, Ph. Traité de botanique, Ed. 2,1: 961. Paris. 1892. 
+ Baron, Philibert. Nouveaux Cae de taille des arbres fruitiers. 1858. 
t¢ Beach, S. A. The thinning of fru California fruit grower 27: 4. 10902. 
§ Beach, S. A. Thinning apples. =e York Agr. Expt. Sta. Bull. 239: 198. 
1903. 
