FRUITING OF APPLE TREES 



EVERY OTHER YEAR 



Reasons Why Apple Trees Bear Heavy Crops Every Other Year — Illustration 

 of a Gravenstein Graft Alternating with the Original Tree 



B. S. Brown 



//('(;(/ of the Horticultural Department, University of Maine, Orono, Me. 



MANY varieties of apples and 

 pears for various reasons bear 

 only every other year. This 

 condition is not uniform the 

 country over, but is more common 

 in the fruit sections of the North 

 and East than in the South or ^^'est. 

 The same is true but to a less 

 extent of the stone fruits. The causes 

 are somewhat varied but are mostly 

 the result of the climatic environment 

 in which the trees are grown. The bien- 

 nial l:)earinj^ habit is apparently not an 

 inheritable trait. Init when it once be- 

 comes fixed in the life of the individual 

 there is little that can be done to 

 change it. 



In the fruit sections where the cli- 

 matic conditions favor the setting of 

 a crop every year, the biennial habit 

 does not exist. In those sections where 

 frosts and rains interfere with the set 

 of fruit, the life processes of the tree 

 are thrown out of balance and the tree 

 gets into the habit of over-working one 

 year and recuperating the next. A nor- 

 mal tree develops fruit buds for the 

 next year at the same time it is matur- 

 ing the present crop. When there is 

 no fruit to mature, an over supply of 

 fruit buds is prepared for the next year. 

 When the time comes, if conditions 

 are favorable, a heavy crop sets and the 

 tree puts forth all its efforts to mature 

 it. This causes such a heavy drain 

 upon the energy of the tree, that no 

 fruit buds are formed for the next croj). 

 After a few years the habit generally 

 becomes fixed and the tree contimics as 

 a l)icnnial bearer. 



If the trees are properly pnmcl and 

 304 



the fruit thinned, while they are young 

 the habit can be prevented to a large 

 extent. When a heavy crop sets on a 

 young tree, it should be thinned enough 

 so it will not be overburdened and can 

 develop fruit buds while maturing the 

 crop. If frost destroys the blossoms, 

 then the grower should reduce the vigor 

 cf the trees l)y cropping the orchard 

 or by giving less cultivation. A heavy 

 pruning in the years when a crop is 

 expected will tend to reduce the amount 

 of fruit and increase the wood growth. 

 Early summer pruning during the crop 

 year will often stimulate fruit buds. As 

 the trees grow older the habit becomes 

 fixed and it is hardly worth while to 

 attempt to correct it. 



That a heavy crop actually reduces 

 the number of blossoms formed for the 

 next year can readily be proved by ob- 

 serving and counting those that appear 

 through two or three years. Instances 

 are not uncommon, where scarcely a 

 dozen blossoms developed on trees that 

 matured a heavy crop of fruit the pre- 

 ceding year. In the particular case il- 

 lustrated in the accompanying photo- 

 graph, one-half of the tree had been 

 grafted to a gravenstein while the other 

 half was of the original variety. For 

 some unaccountable reason each half 

 of the tree chose opposite years for 

 their heavy crop. In the spring it pre- 

 sents an odd appearance by one-half 

 being in heavy bloom while the other 

 Iialf scarcely develops a single blossom. 

 The next year the process is reversed. 



This tree is now al)Out 25 years 

 old and to the writer's personal 

 knowlcflge has l)chnvcd as dcscrilicd for 



