448 POPULAR SCIENCE MONTHLY. 



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 f ull-grown\, will furnish the city of Wash- 

 ington, 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 associa- 

 tions," 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 un- 

 sightly for ornamentation. The average citizen is entirely incom- 

 petent 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 



