STREET TREES. 23 



been the standard street tree of New England, giving to the roadsides 

 and village streets the characteristic appearance which is so attractive 

 to summer visitors. 



The American elm is tall and s])reading, and where i)lanted as near 

 together as is customary on streets and country roads the effect of 

 the mature trees is that of an arch formed by the growing together 

 of their spreading tops. It is of rapid growth and long lived. 



This elm drops its leaves very early in the fall, but it comes into 

 leaf early in the spring. Because of its manner of branching it is 

 especially liable to be split by heavy winds. This trouble may be 

 lessened by selecting and planting specimens with a close, compact 

 habit of growth or possi])ly also by great care in training young trees. 

 Two limbs separating from one another by a very small angle, that 

 is, when they start to grow in nearly the same direction, make a 

 crotch that is liable to split. (Fig. 18.) Where two limbs separate 

 at nearly a right angle or where three or more limbs of about equal 

 size grow from a common point or very nearly so, the crotch is likely 

 to be much stronger. Careful jDruning and training to provide a 

 proper system of branches may be especially helpful with this elm. 



Because of the attacks of the elm leaf-beetle ^ and the European 

 elm bark louse, ^ many handsome trees have been severely damaged 

 or killed before communities were properly equipped for fighting 

 them, for with careful spraying these insects may be kept in check. 

 However, on account of the existence of these pests and because 

 they are gradually spreading to new territory, tree planters should 

 consider carefully whether it is advisable to plant the elm in their 

 localities. Where there is no danger from these insects, this elm is 

 one of the best of street trees. Consultation with the nearest State 

 agricultural experiment station or with the Entomologist of the 

 United States Department of Agriculture would be advisable in order 

 to determine this point. 



The best specimens are to be found in the northern part of region 

 10, although the elm is being grown all over the United States and 

 is proving a valuable street tree even in towns and villages of re- 

 gions where the rainfall is as low as 15 inches. It is not recom- 

 mended for i^lanting in regions 3 and 5. 



The English elm ^ is a tall, oval-headed, compact, handsome tree 

 with leaves smaller than the American ehn and which stay on much 

 later in the faU. In regions 1 and 2 it is at its best, in the former 

 equaling the American ehn and in the latter excelling it. It also 

 thrives in regions 3 and 10 and in the eastern part of region 11. 



The Huntingdon elm ^ is a comparatively round-headed Euroi^ean 

 variety. 



1 Galerucclla luteola Miill. ^ Jjlmus campestris L. 



2 Gossyparia spuria Mod. (Data regarding both * Ulmus hollandica vegeta (Lindl.) Rehd. 

 insects furnished by the Bureau of Entomology.) 



