72 TREES AS GOOD CITIZENS 



center row most satisfactorily. Including tree strips the 

 sidewalks on Pennsylvania Avenue are 20 feet wide, 

 and each of the two roadways 38 feet, leaving 44 feet 

 for the parking strip. 



With streets less than 150 feet wide, it is desirable to 

 use small trees, shrubs or evergreen bushes, instead of 

 trees, for the center planting. Fine park effects may be 

 obtained with these. 



(4) The Center Strip. For narrow streets without 

 car tracks, where the buildings restrict the admission of 

 light, and traffic needs suggest a double roadway, a single 

 row of trees in the center of the driveway may be advis- 

 able. An abundant supply of light and sunshine is 

 essential to the best development of trees. To place trees 

 along the curb of a street where sunshine is in scant sup- 

 ply robs the trees of their chance for proper growth. In 

 general terms, trees cannot be at their best unless their 

 distance from the building line is at least equal to half 

 the height of the buildings. In some streets this cannot be 

 achieved with trees along the side of the roadway, and the 

 center strip offers the solution. 



It may sound contradictory, but the single strip of 

 trees in the center is used for broad thoroughfares as 

 well as for those which are too narrow for sidewalk 

 plantings. A street may be 100 feet in width and yet 

 have sidewalks too narrow for trees; so narrow that to 

 place trees along the curb would result in shutting off 

 light and air from the buildings. By placing the trees 

 in a central row, the decorative and shade-giving qualities 

 are obtained, and the trees have the chance for vigorous 

 growth which would be lacking if they were placed on the 

 narrow sidewalks. Two central rows, of course, are better 

 than one and should be planted where space and traffic 

 conditions permit. 



