WINTER PRUNING EXPERIMENTS WITH APPLE TREES. 155 
centre trees were ahead ; and the crop of 192 1 was so much heavier 
all round than previous crops that the unpruned trees are considerably 
ahead on the three years' average. There is every indication that the 
crop of 1922 will put the open centre trees again in the lead. Biennial 
bearing, however, does not account for the difference in the case of 
' Grenadier ' ; here the unpruned trees, especially those on ' Paradise,' 
have been consistently in the lead, for which no satisfactory 
explanation can be offered. 
It should be said that although in average number of fruits the open 
centre trees of all varieties, taken together, are slightly behind the 
unpruned trees, in average total weight of fruit they are slightly ahead. 
This points to another effect of the open centre pruning, the usual 
increase in the size of the fruit. 
Of all the varieties only one, ' Lord Derby,' has consistently 
produced smaller fruits on the open centre trees ; two or three others 
have done so once or twice, but on the three years' average the fruits 
from the open centre trees are larger, except those of ' James Grieve ' 
on * Crab.' In several cases the difference is very small ; but of ■ Newton 
Wonder ' the individual fruits from the open centre trees have averaged 
throughout nearly 40 per cent, heavier than those from the unpruned 
trees, a difference amounting to more than one ounce a fruit. 
The apparent influence of the stocks may here be referred to. 
When every allowance is made for the mixture of various types of 
' Paradise,' and the evidently large variation amongst the seedling 
' Crabs,' it is still of interest to find that, of all the five varieties 
concerned, the trees on ' Crab ' are larger, on the average, than those 
on ' Paradise ' ; and this in spite of the fact that the smallest in- 
dividual trees of two varieties, 'Early Victoria' and 'Gladstone,' are 
on 'Crab.' Further, of four varieties, 'Early Victoria,' 'Grenadier,' 
' James Grieve,' and ' Worcester Pearmain,' the unpruned and open 
centre trees on ' Crab ' have yielded the greater total number of fruits. 
In the case of ' Worcester ' this is entirely due to the much heavier 
crop of the trees on ' Crab ' in 1921, those on ' Paradise ' having 
previously been ahead ; but of the other three varieties the result has 
been consistent for three years. With the long-spur pruned trees this 
result is reversed, except in the case of ' Early Victoria' (Table III.). 
Until more is known of the types of ' Paradise ' concerned, it will be 
best not to draw any general deduction from this result. 
It is not yet possible to judge whether the open centre trees are 
growing more or less rapidly than the unpruned trees. In actual 
dimensions a number of varieties are larger where unpruned, and an 
approximately equal number where pruned on the open centre system. 
In several cases where the open centre trees are now smaller they 
appear to be catching up in size, but in other cases they are falling 
further behind. It is not worth while to present any figures on this 
point until some definite effect of pruning can be detected. 
In -at least two cases, ' Allington ' and ' Newton Wonder,' where 
the unpruned trees have strongly developed the biennial bearing habit, 
