134 The Fridthuf of Trees in Consecutive Seasons 



extent of about 90 per cent., and, even with the Harpenden results, it 

 is the predominant factor. That it should be more potent at Eidgmont 

 than at Harpenden is easily explained, for the former of these stations 

 is much more subject to spring frosts than the latter, and it is to spring 

 frosts that the failure of crops is generally attributable. 



In the case of the plantation of 117 varieties of apples there were eight 

 trees of each variety, and these were divided into pairs, one pair on the 

 paradise stock,which had been very lightly pruned since they were planted, 

 and one pair on the same stock, which had been more severely pruned ; 

 there were also two pairs on the crab stock, which had been treated in 

 like manner. An examination of the results indicates that the tendency 

 towards consecutive bearing becomes more marked as the age of the 

 trees increases: thus, dividing the results into two periods, 1906-1909 

 and 1909-1913, it was found that the tendency in this direction, taking 

 all the trees together, amounted to 8 per cent, for the first period, and 

 26 per cent, for the second, and the differences were uniformly exhibited 

 by each of the four classes of trees : this is what might be expected, 

 for any habit exhibited by a plant or animal tends to become more 

 established as its age increases. As to the influence of stock ; trees on 

 the paradise stock uniformly showed a smaller tendency towards 

 consecutive fruiting (11 per cent.) than did those on the crab stock 

 (30 per cent.) ; whilst as regards pruning, the results were equally 

 uniform, the tendency towards consecutive fruiting being less marked 

 with the more severely pruned trees (10 per cent.) than with those very 

 lightly pruned (26 per cent.). Apparently, the more a tree is left to 

 natural development, the more does its fruiting become conditioned 

 by extraneous circumstances. 



In the case of observations on a plantation containing different 

 varieties of trees, it is probable that the influence of chance on the 

 bearing of the trees will be unduly exaggerated ; for some of the instances 

 which counterbalance each other will consist of cases where the conse- 

 cutive and alternate fruiting is attributable to the inherent properties 

 of the trees, and not merely to the effect of chance or extraneous 

 circumstances. From the results of general, though, perhaps, not very 

 exact, observations made by fruit growers, it appears fairly certain that 

 some varieties of apples do exhibit a marked tendency towards alternate 

 fruiting, and, doubtless, there are other varieties which exhibit an 

 equally marked tendency towards consecutive fruiting, though such 

 instances, naturally, do not attract special attention. It would be 

 necessary, therefore, in a strict examination of this subject, to treat 



