On the cause of alternate bearing in the apple 
O. BUTLER 
(WITH PLATES I-3 AND A TEXT FIGURE) 
I 
The production of a heavy crop of fruit every other year, or 
alternate bearing, is a well-marked phenomenon in the apple and 
pear, and is not unknown in certain plums and cherries. Alternate 
bearing in the apple, however, has been more particularly recorded 
by American horticultural writers, who have proposed a variety 
of ways of obviating this vexatious propensity. 
Thacher* remarks that trees that are allowed to stand unpruned 
bear only every other or third year, one his remedy for irregular 
bearing is the knife. 
Downing? states that the apple bears in alternate years, but 
that when the fruit is thinned a tree will bear every year “‘as it 
will also if the soil is kept in high condition.” 
Colet observed that apple trees are inclined to bear-in the 
even numbered years (1846, ’48, ’50) and lightly in the odd years 
(1845, ’47, 49) and expresses the view that removing the blossoms 
will change the bearing year. 
Fitz§ recognizes alternation of bearing in the apple and states 
that the most profitable way to obtain annual crops is by proper 
tillage and proper fertilization. 
Thomas} believes that thinning the fruit while the applies 
are small will induce regular bearing and that picking off all the 
fruit in the fruitful year will change the year of crop abundance. 
Maynard states that in most apple orchards large crops of 
* Thacher, J. The American Orchardist, Ed. 2,69. Plymouth, Mass. 1825. 
+ Downing, A. J. The fruits and fruit trees of America, 61. New York and 
London. 1845. 
tCole,S.W. The American fruit book, 87. Boston. 1850. 
§ Fitz, James. The southern apple and peach culturist, 118. Richmond, 1872. 
|| Thomas, = J The American fruit culturist, Ed. 20, 243. New York. 1897. 
q Ma S. T. Successful fruit culture, 44. New York. 1905. 
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