THE ORCHARD.

New Zealand Journal of Agriculture, Volume 50, Issue 5, 20 May 1935, Page 310

THE ORCHARD.

Pruning Operations.

At this period of the year pruning will have commenced or is about to. commence in most orchards, and should be completed, if. possible,, while . the trees are still in : a dormant state,: This . work requires the utmost .skill if the best, results', are to be obtained,, arid should be' undertaken only by experienced persons. Beginners wishing to., become qualified pruners should be kept under constant supervision.

. : The principal object of pruning is to develop and maintain a healthy tree capable of producing a heavy annual crop of first-grade . fruit throughout long life. For the first four or. five. years after planting the aim should be to develop a strong framework capable of supporting a heavy - crop. For the next few years, while . the tree continues, to develop, an endeavour should be made to induce fruit-production. Once .'these results have been accomplished, the object is to maintain good growth,'. avoid over-production, and effect ‘ the suppression of all undesirable growth. ' ' ■ ■ ■ ;

' ; The response to pruning made by trees in different 'conditions of soil arid climate is extremely varied, and even a ■ greater variance is -to "be expected with different classes of fruit and even with different varieties of the same class. . It is therefore quite - impossible - to describe any -detailed system of pruning that can be expected to’ give satisfactory results under all conditions. In : pruning ■ for tree-formation the operator must bear in mind the importance of developing very strong leaders, without which the tree will be unable to support heavy crops. The number of leaders will vary from three to about nine, according to the system of pruning to be followed. These leaders or main limbs should be “arranged spirally around the trunk,'' giving the tree an open centre. At the time of planting three leaders is ample, and these should be shortened .back to about i ft. from the trunk of the tree. The foregoing remarks refer to apple, pear, quince, plum, apricot, peach, and nectarine. .

As the age of the tree increases, so must the. pruning treatment be varied according to the class . of fruit-tree, variety, tree-vigour, &c. It is impossible, here to explain all or even one of these many systems. To be a successful pruner it is essential that the operator . should be able to foretell the subsequent growth that will develop as a ' result - of each cut made... This knowledge can best be obtained by careful observations on the various varieties. Novices in pruning will , be helped, appreciably in their operations by a full realization of • the following, facts.: (i) Peach and nectarine trees bear .fruit on one-year-old wood only ; (2) Japanese plums bear fruit on one-year-old wood and older; (3) apples, pears, and quinces are borne on two-year-old and older and on the tips of one-year-old wood ; (4) European plums. produce fruit on ..two-year-old wood arid older ; (5) apricots produce fruit on one-year-old .wood and on spurs produced on older wood p (6) the more , a shoot approaches a vertical position the stronger is the , growth ; (7) the more a shoot approaches a horizontal position the more its vigour diminishes ; (8) the topmost shoots absorb most sap and outgrow those below; (9) retarding the sap-flow operates against vigorous growth, and, as a result, fruit-buds are more likely to develop; (10) severe pruning increases the sap-flow, which in turn induces vigorous wood-growth unfavourable for fruit-bud development; ’ (11) the vigour of a tree or of a shoot is dependent on- the leaf surface upon it. ■

There has been a radical change in recent' years in many commercial orchards in this and other countries in the ; system of pruning many varieties of apple and pear . trees,' and to a. less extent of stone-fruit

trees. This change involves a method commonly referred to as “ long pruning.” With vigorous-grooving Trees and with certain varieties “ longpruning ” appears to be preferable to many of the older styles of pruning. The system provides for a maximum of five leaders.' In the case of pome-fruit, when the trees are firmly established (one or two years after planting), the leaders are allowed .to grow unchecked until the tree has attained the desired height and- thereafter pruned to an upright' lateral growth. The production of '-fruiting-arms and lateral growth along the entire length of the leaders is encouraged by preventing fruit setting directly on the leaders until the desired result has been secured. Persons desiring further information regarding this ; or any other system of pruning should’ seek the advice of their district Orchard Instructor'. . • '

Tree-wound Treatment.

When it is necessary to employ a saw' for the removal of large branches, the resultant wound is jagged, and, if left untreated, the cambium layer is prevented from forming callus to heal over the wound. Such unhealed wounds permit the entrance of pests (such as woolly aphis) and diseases (such as silver-leaf). Decay is also liable to set in. To treat such wounds it is. advisable’ to trim carefully . the edges of the bark with a sharp knife, leaving a finish with a bevelled edge, and to paint over with coal-tar as soon after the' wound has been made' as is possible.

Cultivation and Manuring.

• The winter ploughing should be undertaken as soon as the foliage has fallen and' the cover-crop has reached the flowering stage. Where phosphatic or potassic fertilizers are being used, these should be sown just prior to. this, the deepest ploughing of the year, and- thereby deposited as close to the roots of the tree as is possible. The ground should be ploughed up to the trees, leaving the finishing furrows midway between the rows to act as a temporary surface drain. To reduce the danger of injuring tree-roots while ploughing, it is a good practice to set the plough to a depth of about 3 in. for the striking-out furrow, and increase the depth every second or third furrow so that the finishing furrow will be about 6 in. or 7 in. deep. ■-P. Everett, Orchard Instructor, Gisborne. .

Citrus Notes

The copious rains following the long dry spell during the summer months have caused much late succulent growth to appear, and this in a number of localities will not have had time to harden before the danger of frost appears. In those localities where frost is common some means of raising the temperature above the danger-point should be adopted. The time is now approaching when the harvesting of citrus fruits will be undertaken. Lemons should be cut when they have attained the .size of from 2| in. to 2| in., regardless of colour, and then stored and cured to make them ready for marketing. . Poorman oranges should be allowed to remain on the trees until they are sufficiently matured to make good breakfast fruit. The practice of picking them green and completing the process of ripening, by artificial means is . not to be recommended.. It is in, the encouragement of the consumption of this orange as a breakfast fruit .that an increase, in the sales can be. sought. Sweet oranges should be left To reach maturity on the trees, otherwise the fruits will not have attained sufficient flavour to command attention. . ■ ■ . ; 7 •. /

— L. Paynter,

Orchard Instructor, Auckland.