6 BULLETIN 205. 



absorb impure and hurtful gases and manufacture the oxygen 

 needed by animals for respiration. Circulation of the air, due 

 to unequal temperature, is likewise promoted by trees properly 

 pruned and arranged ; while the air of basements and cellars is 

 rendered less humid by the removal of surplus water from the 

 surrounding soil through the medium of roots and foliage. 



Secondly, trees add materially to the comforts of a city life. In 

 New York, where the streets are narrow and the houses high, 

 shade, may not ordinarily be considered a matter of prime impor- 

 tance as regards health, but it is a matter of public comfort, and 

 when the heat becomes intense as it has during the past two sum- 

 mers, it may be of great importance in protecting life. Deciduous 

 trees seem specially designed to shield our sidewalks from the 

 glare of the sun in summer and to expose them to its warmth 

 in winter. In many cities, especially in those of Europe, trees 

 are used during the summer as canopies for courts and restau- 

 rants, and the broad shaded sidewalks are often furnished with 

 lunch tables, which are much more attractive than those indoors. 

 Living thus in the open air not only contributes largely to com- 

 fort, but also to health. 



In the third place, trees give pleasure. They soften the hard 

 lines and add attractive forms and colors to the monotony of 

 buildings. Their bright green foliage is eagerly watched for in 

 the spring and the changing colors are a constant source of pleas- 

 ure in autumn. The most attractive cities are those in which 

 well-shaded streets and beautiful parks are most abundant. 

 Lastly, trees add greatly to the value of property and draw men 

 and money to a city. The cities of the future will have wide 

 streets planted with trees as a matter of business. In such cities 

 people will remain far into the summer, when the streets and 

 shops of treeless cities are deserted ; and the business men will 

 reap the profits. During the controversy last summer over the 

 passage of tramcars across Unter den Linden, Emperor William 

 not only objected to the trams, but expressed his intention of 

 planting two additional rows of trees along the sidewalks on this 

 avenue ; and, when some one hinted that the shopkeepers might 

 object, he replied : " Oh, no. People prefer shade to sun in sum- 

 mer, therefore more people would pass through a shady street. 

 Consequently it would be better for the shopkeepers. " 



