Page:Popular Science Monthly Volume 54.djvu/466

448 thousand trees were planted, consisting of silver maples, Norway maples, American elms, American and European lindens, sugar maples, tulip trees, American white ash, scarlet maples, various poplars, and ash-leaved maples. . . . A careful count was made of the trees in 1887, and by comparing this with the number of trees since planted and those removed, there is found to be more than seventy-eight thousand trees, which if placed thirty feet apart would line both sides of a boulevard between Washington and New York. These consist of more than thirty varieties." Mr. Richards adds: "The planting and care of trees in Washington grows from year to year, and the future will probably demand more skill and judgment than in years past. About twenty thousand dollars is spent annually, most of it in the care of old trees. From one to three thousand young trees are planted during the spring and fall of each year. The nursery has several thousand of the best varieties ready for planting."

The opinions of these authorities and the success of the work in Washington, now extending over a quarter of a century, determine beyond all question the feasibility and practicability of successfully cultivating trees in the streets of cities. And if any one doubts the power of trees cultivated in the streets to change the temperature of a city let him calculate the amount of foliage which the seventy-eight thousand trees, when full-grown, will furnish the city of Washington, taking as his basis the fact that a single tree, the Washington elm, at Cambridge, Massachusetts, when in full leafage, equals five acres of foliage, and that one acre of grass emits into the atmosphere 6.400 quarts of water in twenty-four hours, a powerfully cooling process.

We have, finally, to consider through what agency the proposed cultivation of trees in the city of New York can be accomplished most rapidly and successfully. Three methods may be suggested, viz.: 1. Encourage citizens each to plant and cultivate trees on his own premises. 2. Organize voluntary "tree-planting associations," which shall aid citizens or undertake to do the work at a minimum cost. 3. Place the work under the entire supervision and jurisdiction of public authority. The first method has been on trial from the foundation of the city, and its results are a few stunted apologies for trees which are useless for sanitary purposes and unsightly for ornamentation. The average citizen is entirely incompetent either to select the proper tree or to cultivate it when planted. Tree-planting associations have proved useful agencies in exciting a popular interest in the subject, and in aiding citizens in the selection of suitable trees and in cultivating them. The Tree-Planting and Fountain Society of Brooklyn, under the very able