12 SHADE-TREES IN TOWNS AND CITIES 



uals, numbers eleven. The species represented by more 

 than a thousand specimens number nine. 



It has been thought best, however, to give a list of the 

 trees from which selections for street-planting are generally 

 made, in the hope that this list will be helpful to the planter 

 in selecting his material under certain conditions. The trees 

 are described from the point of view of their desirability or 

 undesirability for street-planting. Undoubtedly there are 

 trees other than those enumerated which, under favorable 

 conditions of soil, climate, and care, will make good street- 

 trees. 



THE MAPLES 



Norway Maple (Acer platanoides Linn.). This tree ap- 

 pears to be the best maple that we have for street use. It 

 comes to us from Europe, its range extending from Nor- 

 way to Switzerland. It withstands city conditions well and 

 seems to have remarkable resistance to insect attack. While 

 the tussock moth and the leopard moth frequently injure the 

 tree, the greatest damage is sometimes done by certain 

 species of plant lice which lodge themselves on the under 

 side of the leaves, causing them to dry, curl up, and fall 

 from the tree. The natural enemies of the plant lice, how- 

 ever, are very numerous, and the spraying of this species of 

 tree is seldom necessary. 



On streets where the houses are in solid rows this spe- 

 cies of tree is to be preferred, for the reason that it does 

 not grow so large as the native hard maple. The trees 

 should be set about thirty-eight feet apart. Care must be 

 taken to prevent their heading too low and making too 

 dense a shade. This can be easily done by timely and skil- 

 ful pruning. 



