68 NEIGHBORING IMPROVEMENTS. 



STREET TREES. 



The subject of street trees comes properly under the head of 

 neighboring improvements. It might be inferred, from the modes 

 of planting recommended in the preceding pages, that a variety of 

 trees will be recommended for one street in preference to a single 

 sort. On the contrary, the effect is much better, on a straight 

 street or road, to have an avenue composed of a single species of 

 tree only. To attempt the varieties of park scenery on an avenue 

 is as much out of place as to compose a park of straight rows of 

 trees. There ought to be but one variety of street tree on the 

 same block, at least, and the longer the continuity is kept up the 

 nobler will be the effect. Street trees are usually planted quite too 

 close together. For wide avenues (where alone such great spread- 

 ing trees as the elm, sycamore, silver maple, and silver poplar 

 should be planted), from thirty to fifty feet apart is near enough, 

 and thirty feet is the least distance that any street trees should be 

 planted from each other. The finest deciduous trees are those 

 already most commonly planted elms, maples, and horse-chest- 

 nuts. The white pine is a noble street tree, very little used. It 

 deserves to be ;. but as it must be planted of smaller size than the 

 deciduous trees, in order to do well, and therefore requires box pro- 

 tection during a greater number of years, it should only be planted 

 where such protection is sure to be given. No trees should be 

 planted, in streets, which do not come early into leaf, or which have 

 disagreeable blossoms, or which bear nuts or eatable fruit, or the 

 leaves of which are subject to worms, or do not drop promptly and 

 dry after the first severe autumn frosts. The different varieties of 

 the maple, the horse-chestnut, the weeping elm, and the English 

 and Scotch elms, all unite to a great extent the best qualities for 

 street trees. The linden is peculiarly subject to worms, and should 

 not, therefore, be planted in streets. The elm, near the sea-coast, 

 is also infested by a species of worm, which does not, however, 

 seem to be very annoying in the interior. The tulip tree, or white 

 wood, is rather difficult to transplant, and not adapted to any but a 

 rich warm soil ; but, once established in such a soil, it makes an 

 elegant street tree. The oaks grow too slowly to be popular, and 



