Care of Street Trees. 71 



overtopping them. For the best landscape effect and for the 

 best development of the trees themselves it is advisable to use only 

 one species on a street. 



Uniformity should also be secured in the distance apart at 

 which trees are planted, and they should be as nearly as possible 

 even sized. In Washington, they keep in the city nursery trees 

 of all sizes, so that when one dies on the street it is replaced by 

 one of equal size. This practice can be followed profitably only 

 while the trees are comparatively small, as the transplanting of 

 large trees is very expensive. 



Selection of Species. 



In selecting species of trees for street planting regard should 

 be given to their different habits of growth, light, air and water 

 requirements. Where the streets are narrow, smaller more up- 

 right trees, such as the Norway maple or cottonwood should be 

 selected ; on wide streets, the tall elm, with its spreading crown, 

 the sugar maple or the linden are better adapted. On high, dry 

 situations species which require less water, such as the scarlet 

 oak or horse chestnut, thrive better than elms or maples. The 

 horse chestnut seems to withstand smoke and other injurious gases 

 better than other species. 



Selection of Planting Stock. 



It is of the greatest importance to secure thrifty well-devel- 

 oped stock for planting. Too frequently the young saplings are 

 just dug from the woods, their roots chopped down to a conven- 

 ient size, and the top cut back, so that the shape of the tree is 

 spoiled for a time. Every tree which is to be planted on the 

 street should be grown in a nursery and transplanted several 

 times, so that the roots will be trained to grow in a compact* fomi, 

 before being finally placed on the street. In the nursery too, by 

 judicious crowding, straight, tall and clean trunks can be develop- 

 ed, thereby lessening the amount of pruning necessary in after 



life. 



Too Close Planting. 



One of the most common mistakes made in street planting 

 is placing the trees too close together, so that their crowns do 



