Are Shade-Trees Healthful?
A WRITER in the London Lancet takes the ground that the general custom of planting shade-trees in the streets and lanes of cities is to be deprecated since it undoubtedly interferes with the free circulation of air. It might be supposed that trees would aid in purifying the air by freeing it from carbon di-oxide; with which it becomes contaminated by the respiration of animals, the combustion of wood and coal, and vegetable and animal decomposition; but a moment's consideration will be sufficient to convince any one that for such a purpose the few trees which could be made to grow along the sides of narrow streets would be wholly insufficient. A few of the great furnaces in our cities would supply a whole forest with carbon di-oxide. More than this, in all cities there are produced in large quantities numerous gases which are alike injurious to animal and vegetable life. Trees would certainly be no help in this regard. Again, tall trees, with dense foliage, cast a shade upon the houses, and so prevent the entrance of sunshine into dwellings, thus depriving the inmates of one of the most potent of all disinfectants, and the most effective of tonics. Furthermore, it is evident that a large number of trees in a city with narrow streets will very seriously obstruct the free circulation of air. The gentle summer breeze, as well as the stronger winds of fall and winter, is kept above the houses by the numerous obstructions, so that the city is not well ventilated. Town and city ventilation is a matter of as much importance as house ventilation. It is, indeed, of greater importance, since house ventilation is useless unless the outside air is free from contamination. Cities located in a tropical or semi-tropical climate, should have wide streets; then they may also enjoy the luxury of shaded walks during the heat of summer. The objections urged against trees planted along the sides of streets does not, of course, apply to trees in parks. The more parks filled with trees and other forms of vegetation a city can have, the better.—Good Health.