Pruning apple trees of vigorous Bankroft varieties, Starking, Close and Beauty of Boskoop.
Pruning apple trees of vigorous Bankroft varieties, Starking, Close and Beauty of Boskoop.
Currently, intensive orchards play a key role in the production of apples, established in the past two decades, most of which have entered the period of full fruiting. Apple trees grafted on vigorously growing rootstocks were usually planted at 6X4 and 7X5 m spacing. These orchards thanks to the large number of trees on 1 hectares generally give very high yields of fruit. However, a serious problem in these orchards is obtaining good quality apples, which, due to the high density of trees, tend to be undyed, or too small. The main task of cutting is to regulate crown density, limiting the size of the crowns and thus creating conditions for the development of pretty apples. Individual varieties of apple trees often require different procedures.
Pruning apple trees of vigorous Bankroft varieties, Starking, Close and Beauty of Boskoop.
Apple trees of the above-mentioned varieties when planted at a spacing of 6X4 or 7X5 m, are not more than 10-15 years apart. Longer maintenance of the orchard requires intensive crown pruning or even cutting and grubbing up of tree parts. Apple trees grow to a height at this age under uncontrolled conditions 4-5 m, the crown span is up to 5 m. The trees in rows form a single, compact wall. There is just enough space at the bottom in the row spacing, that the tractor with the sprayer can hardly squeeze through. The upper branches of the adjacent rows almost touch each other (rys.a, b).
Drawing. Method of cutting trees in an overly compacted orchard: a - view of the orchard from the inter-row side, on the left - overgrown crowns in the upper part, on the right - the same crowns after trimming the tops; b - view of the orchard from the side of the row, on the left - branches of neighboring trees overlap, on the right - crowns after branches thinning; c - view of the orchard from above, on the left, a circular shape of crowns, on the right, the shape of the crowns has been changed to oval.
Mutual shading of trees causes, that the lower parts of the crowns bear fruit poorly. The fruits are small and have no blush. The upper parts of the crowns grow very vigorously and generally bear fruit abundantly, but they are not always sprayed effectively.
Intensive pruning in over-compacted orchards should be started before adverse symptoms develop, that is, 7 or 8 years after the orchard was planted. First of all, you need to limit the height of the trees to approx 3 m. The guides of the trees are best cut to the height of an outstretched arm, that is, slightly above 2 m. As a rule, twigs grow above the guide, therefore the total height of the trees after pruning should be about 3 m. The lower hanging branches need to be cut to a height of approx 0,5 m. They drop down under the mass of fruit, therefore, when harvested, they will reach almost to the ground.
The permissible crown span depends on the planting density. After cutting, the working lane between the rows must have at least 2 m, which means, that the diameter of the crowns in the 7X5 planted orchard may reach 5 m, in the 6X4 planted orchard according to 4 m, and in rowed orchards, usually planted at 4 m row from row, crown thickness up to 2 m. In the rows, the canopy of the trees may touch each other, and even the branches of neighboring trees can overlap, but not more than to 1/3 length.
In order to limit the span of the crowns, initially it is enough to slightly shorten the branches that extend onto the working street and interfere with the operation of the machines. In the case of intensive overgrowing of the street, the branches facing the inter-row should be completely removed, leaving these, which are facing the line of the row. By cutting, we gradually change the cross-section of the crowns from circular to oval, and even a line (Lynx. c). The shape of the crown in the vertical section plays a large role in insulating the branches with sunlight. The best sunlight is obtained in conical crowns, which have a conductor and horizontal branches, the upper ones are clearly shorter than the lower ones. If the fruiting trees deviate significantly from the conical form, they should be kept open from above, so that the sun's rays can reach the lower branches in this way. In rowed orchards, it is necessary to prevent the upper part from growing over the lower part at all costs.
