94 BUTLER: ALTERNATE BEARING IN THE APPLE 
The data in the above table show that in the trees under 
tillage alternate bearing is more pronounced than in the trees 
under sod-mulch; and that fertilization emphasized alternate 
bearing whether the trees were in sod-mulch or under cultivation. 
The trees grown in sod-mulch without fertilization bore more 
uniformly than under any of the other cultural methods used, 
which signifies that in the trees so treated there was a more 
uniform yearly production of spurs than in the others, which in 
other words means that the yearly growth of the trees must also 
have been more uniform. 
An example will make the above statement clear. Let us 
assume that we have an apple tree in full bearing and that we 
have six consecutive years of bearing wood already formed. Let 
us say that the youngest growth developed in 1916, then the oldest 
was produced in 1908. Now if the yearly growth has been equal 
throughout, the number of spurs formed will have been equal and 
the crops produced identical (TEXT FIG. 1). 
1908 . 1909 
1910, 1911, 1912 , 1913, 1914, 1915, 1916 
\ 
13 14 15 16 
Fic. 1. Diagrammatic drawing showing method of fruiting of the apple. 
@ = Bearing year; the numbers subjoined in the figure indicate year of fruit- 
fulness. 
“~ = One year’s growth. 
> = Two years’ growth. 
Now let us suppose that the yearly growth was unequal, then 
the number of spurs formed will have been unequal and produc- 
tiveness will have exhibited corresponding fluctuations. 
There is, therefore, a direct relation between growth and 
productiveness. In order to produce annual bearing in the apple, 
and this is a sine qua non, one must cause the development of - 
flower-buds to take place in about equal numbers every year. 
In other words, the bearing surface of an apple tree after it has 
reached maturity should not be allowed to change, which means 
that the new growth should be regular and always sufficient to 
