Trees for Town and City Streets. 37 



owing largely to the European poplar canker, but otherwise is a 

 satisfactory tree for these conditions in all parts of the United 

 States. The trees may be planted as close together as 30 feet. 



None of the other poplars have much to recommend them for 

 street planting. 



RUBBER TREE. 



The rubber tree is a large-headed handsome evergreen, suitable 

 for regions 3 and 5 and the southern parts of regions 2 and 13 when 

 the use of an evergreen tree is warranted. 



SILK OAK. 



The silk oak, or Australian fern, is a large, handsome tree that 

 succeeds well in regions 2, 3, and 13; also in region 5 if provided 

 with a reasonable amount of moisture, as it stands drought remark- 

 ably well. It is covered in early summer with orange-colored 

 flowers. 



SWEET GUM. 



The sweet gum (fig. 25) is adapted to regions 11, 12, and 13, 

 especially on sandy lands. It forms an oval-headed, handsome tree 

 with star-shaped leaves that assume a particularly brilliant hue in 

 the autumn. It is better adapted to suburban conditions than to the 

 heart of a city.' Toward the northern limits of its successful cultiva- 

 tion it is difficult to transplant, while in the warmer sections of the 

 country it can be moved with comparative ease. It should be trans- 

 planted only in the spring. 



SYCAMORE. 



The sycamore, also called the buttonwood and buttonball tree, is 

 a large, open, spreading, quick-growing tree native along water- 

 courses. It is adapted to regions 1, 2, 3, 4, 9, 10, 11, 12, and 13 

 and is worth testing in regions 5, 6, 7, and 8. Its habit of shedding 

 its outer bark in large flakes, leaving the white new bark showing in 

 large patches, makes it a conspicuous tree wherever grown. The 

 fruits are balls 1 inch or more in diameter and are sometimes ob- 

 jected to because they make dirt when falling; also the shed bark 

 is considered objectionable. It is such a strong-growing, handsome 

 tree and succeeds so well under city conditions that it is being planted 

 more and more frequently. It will stand more pruning and shaping 

 than any other street tree. Without pruning it is too large for ordi- 

 nary streets unless spaced at almost double the usual planting dis- 

 tance, with the trees staggered along the street instead of being 

 planted opposite. Its high head and open habit of growth are dis- 

 tinct advantages for street planting. Its foliage, too, is a light green ?j 



