SHADE TREES THE RVALUE IN TOWNS AND CITIES

Dominion, Volume 12, Issue 220, 11 June 1919, Page 5

SHADE TREES THE RVALUE IN TOWNS AND CITIES

Tho Director of Parks and Reserves, Wellington City Council (Mr. J. C. M'Kenzie), read tho following paper at the recent Town-planning Conference:— Tho cultivation of trees in cities is beneficial in many ways, and in tho realisation of the city beautiful shade trees play a -most important part. While visitors .admire the beautiful buildings of Paris and Washington, all admit that tho chief attractions ore their beautiful avenues of shade trees. The 88,000 street trees of Paris, in the upkeep of which .100 workmen are constantly employed, 6how the possibility of cultivating largo trees in streets and public places under adverse-circumstance!-. From tho viewpoint of health we need but recall a few well-known facts. Trees help to purify the air 'by absorbing the carbonic acid gas that is exhaled by man, and giving back"-the pure oxygen ho needs. The animal and vegetable world, therefore, complement each other,. aud ono furnishes the conditions and forces by which tho other maintains life end health. Tho first cost of planting is very small compared with other street improvements, and: while the costly road surface will deteriorate with njjo and reed constant repair, the trees, it cared for, will thrive find grow, and', the'first cost 'will bo,'insigpitica.ut when.comp'ared with their increased value' as years go by, Probably no work in horticulture requires more judgment and good management than planting street trees. The soil is invariably bad, then dust, injuri oiis smoke, and gas leaks make their establishment hard. It is necessary, there, fore, that the selection of varieties should bo limited to those kinds that thrive under these adverse conditions. Taking all points into consideration, the most satisfticfary trees are the elms, oaks, limes, and chestnuts. Tives for this purpose require to be well trained, straightstemniexl plants of nearly a uniform height of not less than 10ft.,' with the head beginning at about 7ft., and the stem fully 3 inches in diameter. Although tho tree is to be formal in shape, its' natural habit of growth should bo preserved, ■at !he oame I time keeping it symmetrical and fullheaded. The top, when planted, should 'bo cut back to about one-third of ita length. For the best results the activo leaf surface and tho active rootlets must be in direct proportion. The interdependence of tho roots and leaves is complete. . If the leaves are stripped ofl by the wind, or attacked by blight or insect pests, a corresponding' amount of roots die from Jack of nourishment. It roots are Teduced in transplanting, the foliage of'the whole top mil Buffer in proportion and vory often not survive the shook. In ■ tho nursery tho tree should be trained to withstand the hard"its final home. Annual transplanting cuts the large anohor loots and develops lateral rootlets, just us thp lateral branches are developed when thfl leader is headed back. In this way a bunchy fibrous root system is obtained that will sustain the demands of the'top when the tree is finally planted. Equally as important as the tree, if not wore so, is tho preparation of soil. At least 63 cubic feet of ground Should be excavated from the hole. I usuallr make this 7ft. long, \3ft. wide, arid 3ft. deep, Good top soil, enriched with well-lotted manure.or bonemeal, should then take the place of cloy, stones, broken bottles, -tins, and rubbish of all descriptions that wo usually encounter. The perfect soil is a deep, loose loam winch permits satisfactory soration and drainage, but this is not usually met with. Besides soil to feed on, a' tree, like an animal, needs air for respiration. Not only the leaves, but 'the surface of the' twigs, branches, and roots are covered with breathing pores, which conduct air into the interior. That roots breathe is not. often realised. When a tree, is planted too deeply or the ground around it is raised in course of improvements many a tree is lost. ' In planting, the treo should be set about as deep as it stood in the nursery; the roots next spread naturally; sift fine soil around them', and work 'it in' clesu with .a pointed stick, so that no pua-o remains unfilled, to within about four inches from the top. This is then firmly rammed, and filled with water. When it has taken all. the water it can'hold coyer with three inches of loose soil to act as a mulch to retain tho moisture. A 12ft. stake should ljo driven into the ground alongside the tree to support the stem, to >kecp it rigid and prevent It from being' bent out of shape by strong winds. The constant swaying of the stem also interferes with the establishment of fine hair-like feeding roots >.n the soil. In order to keep tho tree growing, constant care is necessary, and cultivation by keeping the ground broken up. To retain the moisture is as important for the tree as for tho flower garden or field crop. If the tree is on tho pavement or among concrete nags, iruu grids that are removable will be necessary to let this work go on. A few handfuls of bonemeal worked into tho soil periodically will help to push tho tree ahead. Water regularly in dry weather. I have used up 10J000 gallons of water-a week on n street of trees loft, high, and. they absorbed every particle. If these directions are followed you can scarcely lose t t tree in transplanting,'and in a few years you will have a. tree worthy of your efforts, and one to take a civic pride in for all time.