Influence of pruning on the regularity of fruiting
Many varieties of apple trees, pear and plum trees show a tendency to alternate fruiting, that is, producing a crop every other year. Alternate fruiting occurs primarily in naturally very fertile varieties, which have the ability to bear fruit simultaneously on all fruiting shoots. If all the fruit-bearing shoots on the tree bear fruit, they inhibit the formation of flower buds for the next year.. The following year, the tree does not bloom and bear fruit, which in turn causes a very abundant bud formation and an equally abundant fruiting a year later. Thus, the tree enters the cycle of alternating fruiting. Intensive cutting of trees prevents alternate fruiting.
Regular fruiting can be achieved by cutting these varieties, which do not show a persistent tendency to yield a crop every other year. Among the apple trees, such varieties include Lobo, Mclntosh, Spartan, Jonathan, Bankruptcy in inside. Apple trees bear fruit stubbornly alternately like Olive Inflancka, Melba or Wealthy cannot be induced to fruiting annually by pruning, unless it is used together with other agrotechnical treatments, such as intensive nitrogen fertilization and thinning of fruit buds. Even if cutting in the mentioned varieties does not completely eliminate the alternation of fruiting, it does, that the fluctuations between the yields from the following years are smaller.
In order to counteract alternating fruiting, cutting of small twigs and shoots is used. In the year of the expected high harvest, some of the shoots with flower buds are cut, to reduce flowering. It doesn't help much at first, because the remaining shoots produce more fruit and the yield is not diminishing. However, pruning stimulates the trees to create long shoots, which in the first year of growth are not yet able to form flower buds and constitute a reserve for the following years. After 2-3 Over the years, a certain state of equilibrium between fruit-bearing shoots is formed in the crown of a cut tree, and long shoots. When fruit-bearing shoots bear fruit in a given year, the shoots are younger, newly grown, are a reserve, where the buds are formed and the fruit grows in the following year.