66 SHADE-TREES IN TOWNS AND CITIES 



provided, at least four feet in width, along which trees may 

 be planted. If the width of the street permits, these strips 

 may be made up to ten feet or more, but a width of four 

 feet is about the minimum space along which trees can be 

 planted. Frequently no planting-strip is provided at all, or 

 it is made so narrow that it is impossible to set out trees. 



Width of Roadway.— The determining factor of the width 

 of the roadway is the amount of vehicular traffic it carries, 

 and it should not be made wider than necessary. In the first 

 place it costs more to construct and maintain a wide road 

 than a narrow one. The wider the road the greater the 

 volume of dust, and the closer the road comes to the side- 

 walk the nearer the dust is to the pedestrians. A broad strip 

 of turf between walk and curb enhances the beauty of the 

 street, and gives the trees a better chance for life and vigor. 



In some cities and towns the streets are laid out with no 

 provision for trees, and the widths of the roadway and the 

 sidewalks are not in proportion to the use of the highway. 

 In Carlisle, Pa. , for example, most of the streets are sixty 

 feet wide. Although the street traffic is not extensive, the 

 roadways are made forty feet wide and the sidewalks ten 

 feet wide. The houses are built close to the sidewalks, and as 

 soon as the trees become of considerable size the branches 

 grow against the buildings. As a result of such conditions, 

 an ordinance was enacted in Carlisle requiring the setting 

 of the trees in the gutter. It is evident that such a system 

 of tree-planting is very bad. Trees planted in the gutter 

 become an obstruction to the highway, they prevent the 

 running off of storm-water, and prevent the keeping of the 

 roadways clean. Plate 32, Fig. 5. 



Divisions of the Street.— The division of the street into 

 walks and drives, and the determination of the number of 



