STREET PLANTING.

Poverty Bay Standard, Volume IX, Issue 958, 6 July 1881, Page 2 (Supplement)

STREET PLANTING.

No. I. [From the Melbourne Leadcr.~\ As the season for planting has arrived it may not be amiss to say a few words on the subject. It is patent to all that hitherto street planting in the neighborhood of the metropolis has not been a decided success. 'Chat in other towns in Victoria a very much greater amount of success has been achieved may be due to some extent to more favorable circumstances, and certainly in some cases, to a greater amount of skill having been brought to bear in the work. There has been no stint of money by the Melbourne Corporation, either iu the purchase of good trees, the preparation of the ground, or the means of protecting the trees after being planted, but it is a common opinion, which we cannot do otherwise than endorse, that the bulk of the money has not been laid out to the best advantage. It must be taken into account that disadvantageous circumstances of climate have to be contended against, and, in the case of the city of Melbourne, local circumstances are also to a great extent unfavorable. The unfavorable climatic influences consist in the occasional extremely high temperatare so detrimental to the welfare of many of the deciduous trees of temperate zones, which are the best adapted to the purpose ; then the cutting drying winds, combined with the great heat, and the frequent lack of moisture, effectually prevent the very existence of some of the most suitable kinds, such as the Linden and others, which in moister and more temperate climes are the beau ideals of shade trees. One of the greatest drawbacks to the welfare of street trees in Melbotfime is the bad soil, though that may to a certain extent be remedied ; but there are others common to nearly all cities against which [the remedies, to be of any useful effect, must involve a large expenditure. The principal of these are gas pipes, in the neighborhood of which it is extremely difficult to induce trees to thrive. Sewers, drains, asphalted footpaths and macadamised roads are all extremely detrimental. Experience teaches that wherever gas-pipes lie in the ground there is certain to be some extent of leakage, the emanations following the course of the pipes, and poisoning the soil to such an extent as to destroy whatever root may exist within the bounds of their influence. So that, unless some means can be adopted to prevent the gas from coming in contact with the roots, ihe destruction of the trees is only a question of time. The only effectual remedy of which we have ever heard or read —and it is a very expensive one —is to isolate the pipes by enclosing them in air-tight cemented masonry and unless that is done thoroughly, to plant trees in the neighborhood of gaspipes is simply a waste of time and money. Sewers and drains, if generally less deadly in their influence, are in many cases sufficiently noxious to cause the destruction of vegetable life. But, supposing none of those evils to exist, there, are still the macadamised roads and the asphalted footpaths to contend against; and here the deficiency in knowledge and experience of those to whom is entrusted the superintendence of tree-planting in the city of Melbourne is painfully apparent. It is patent to all possessed of even a slender knowledge of vegetable physiology that plants cannot thrive in soil from which atmospheric influences are excluded ; and besides the exclusion of air from the soil, it becomes so hard and so dry that the roots of the most vigorous kinds of tree are unable to make way in it. Of this fact there are numerous examples to be seen in the suburbs of Melbourne, where trees having been planted on footpaths of sufficient width to admit of a considerable space of bare soil outside the flagging, they have thriven and grown well for a few years, until the increase of population having necessitated the widening of the footpaths, and these being covered with the tar pavement, the air is completely excluded from the soil, while on the other side the channel is curbed and paved, and the macadamised roadway brought up to it, the consequence being that, at once the growth of the trees is checked, they lose their leaves even before the summer is over, speedily put on a stunted appearance, and die away by inches. Our planters appear to be either unaware of the evil consequences of subjecting the roots of trees to such conditions, or of the means required to obviate them. The roots of a tree are placed in the soil, and then

the paying, flagging, asphalting, or what not, is laid down to within a few inches of the stem, so that though a good specimen may, and generally does, make a fair growth the first season, afterwards, from the soil becoming hard, dry, and charged with the gases of its own decomposition, the roots are asphyxiated from want of air, or poisoned by the accumulation of noxious matter. Wherever a tree is planted a space of several feet should be left uncovered around it; this space may be, if necessary, covered by a moveable grating, so that the air may have access, and the soil may be mulched or watered whenever necessary. It is of the utmost importance that the trees should be placed in suitable soil. It is frequently found that either the street has been raised to the necessary level by filling up with rubbish, or lowered by clearing away the surface soil, or the soil may be naturally of inferior quality ; in any such case, it is imperative that the soil be made good, at whatever cost. It is not sufficient that a hole of a few feet square should be made and refilled with fertile soil. Where the natural soil is very bad it should be removed to the extent of ten or twelve cubic yards, and to a distance of six to eight feet from the centre , for if it is considered to what a distance the roots of a matured tree will extend, it becomes quite clear that the holes usually made are inadequate, under the best circumstances, to afford root room for longer than a very few years. Even when the natural soil is tolerable in quality it is of great advantage to give a tree a good start; it may then, after attaining a certain amount of vigor, be enabled to push its way in soil that a weakly subject could scarcely penetrate. 'lhe position of the line of trees is generally governed by circumstances. The best is inside the footpath in the case of ordinary streets, but should the footpath not be of sufficient width to admit of the trees being placed at least 2 feet from the edge of the kerb, it should be either widened sufficiently or the attempt to plant trees abandoned. With regard to the proper distance apart for the trees, that depends mainly on the size to which the kind of tree used may be expected to attain, and partly to the purpose which it is to subserve, so that no rule can be given that will apply to all cases. The planting of the trees should not be entrusted to any but a skilful and experienced man, who thoroughly understands the nature of the work, both as regards the depth at which to plant, the pruning and arrangement of the roots, and the replacement of the soil. Pruning of street trees is an operation of considerable importance, but for the most part it is either altogether neglected or performed in an imperfect manner. In the case of young trees, nearly all the pruning they require should be done during the season of growth, when all shoots that are not required—especially rival leaders —should be destroyed, and others that are outstripping the rest in strength reduced by pinching off their points. The style of pruning in after years must depend on the purpose which the tree is to subserve ; if it is to maintain a natural appearance little pruning will be required, but if for a shade tree, then the proper plan is to prevent the upward growth by stopping the leading branches, and so increasing the vigor of those taking a horizontal direction. In our next we shall take into consideration the kinds of trees suitable for various situations and purposes.