The Garden

Otago Witness, Volume 15, Issue 1487, 15 May 1880, Page 7

The Garden

[Specially written for the Otago Witnm.) By J. N. Grigor. PRTJNING. WHEN TO BEGIN. Pruning should be commenced'" in yonng plantations as soon as the trees are seen to require it. This generally happens with deciduous hardwoods when they have produced three or four years' growth, but with the acaoias, and eucalypti when they have made very thriving two years' shoots. The pruning-knife is the only implement used, and when it is early and frequently attended to, no other tool is required during the whole progress of forest pruning. It is therefore advisable that pruning should be commenced early, in order, as it were, to repress irregularities in the bud, or at all events to check an irregularity as soon as it is known to be one. For example, when a shoot occupying the position of a branch, ascends in competition with the top, or leading shoots, and is allowed to go on for years aaoending, the stem of the tree will have a forked character: or if the competing portion be pruned off_ close after it has acquired a large size, the timber will be rendered unsonnd. Nothing can more readily deteriorate the value of a tree than amputating large branches close to the trunk. > The unsightly wound created will be several inches in diameter; the influence of the sun and j weather cracks the timber which imbibes water; j rottenness supervenes in the bole| and, although the wound will collapse, and in time . bo covered over, yet the timber remains unsound. i

Explanation.— When it is necessary that a large branch should be removed, it should be amputated a foot from the main stem, or olose to the place of swelling at its junotiqn with the trunk, which ia frequently six to eight inches in length. But if the shoot from whioh this aspiring limb took its rise had been stopped in the first or second season of its growth— in February or March— the tree might have been grown with a clean, regular, tapering stem. Towards the autumn, or when the leaves have nearly ceased to carry on their functions, pruning should begin. If a branch be cut off when in foliage, the remaining portion draws the sap, and prevents an effusion at the wound. But if the foliage be not fully expanded, the amputation of a branoh is followed by a flow of sap, which appears to drain from every part of the tree, weakening and oheoking growth from exoessive bleeding, and oanker is apt to ensue. Pruning in early autumn has this advantage over winter pruning : that no sooner is the branch removed than the descending sap imma. diately cicatrises the wound, whioh heals up in the space of a few weeks. # Proof.— The close amputation of large branches should, as already Btated, never occur, no matter how soon the wound heals over ; for in cutting up the bole (after the tree has been felled the new layer of wood that covered the wound will be found to be only in close contact with the surface of the out, which has decayed inwards, and the unsound wood is thus embodied by the living'matter covering, but not coalescing. Shortening to the first twigs, preparatory to its final removal the following season at the swell or bulge, at whioh point the diameter is not so great as at its close junction with the_ trunk— consequently a much smaller wound being made and sooner healed— is the safest and best Bystem to prevent deterioration in value. Young Trees.— ln pruaing young plantations intended for a profitable return, and where ornament and such things are not the object, it must be borne in mind that growth is always corresponding to the action of the leaves and branches j if these are in due proportion and in perfect health and vigour, the knife will always be found rather detrimental to luxuriance and constitutional energy than beneficial. A very common error in pruning young trees is the injudicious system of cutting off the side branches for a considerable distance up the stems, whioh weakens their energies, and causes them to grow with lean and slender stems. # By taking off these branches, the stem is deprived of all the leaves which would attract and elaborate the sap, thus preparing nourishment for the growth of the stems ; and the trunk of the tree does not increase in size so fast as when the side branohes are allowed to remain for a time, and then pruned away gradually. With young trees, it is better to shorten only the aide branches when they are of a moderate length, All should be left undisturbed in the first instance, unless such of them as may require a oheak if growing too strong for the others or for the leader. Small branohes along the Btem should be left till they approach the dimensions by whioh the removal of the others is regulated. This system should be followed up till the required height of the stem is attained ; after whioh the branches composing the top should be allowed full freedom, in order to increase the diameter of the stem.