STREET TREES 613 



and a symmetrical crown, commencing at 7 to 9 feet from the ground. It is 

 sometimes difficult to find trees that will in every respect meet these specifi- 

 cations and it might then be well to agree to a smaller diameter, but to insist 

 on well-formed specimens. Individual perfection, symmetry and uniformity 

 are fundamental principles in successful street planting. For this reason, it is 

 important to plant trees of the same species on the same street or at least on a 

 stretch of several blocks ; to have all trees of uniform size and to set them out 

 at equal distances apart. Thirty feet apart is a suitable distance for most 

 street trees and a tree like the elm should be allowed 60 feet. It is in the 

 realization of just such points wherein He the advantage in having a munici- 

 pality undertake such work. If left to the citizens to do this individually, the 

 trees will be planted either too close or too far apart. Many species will be 

 mixed on the same block and many blocks will have no trees at all. 



As to the selection of the species that will, of course, vary with the local 

 conditions. In a general way, however, i)ersons in the East will find the 

 Oriental sycamore the hardiest of all for street planting. The sycamore has 

 lately been slightly afflicted with a leaf blight (gloeosporeum nevisequum), but 

 the disease has not become general enough to do serious damage. The Norway 

 maple is another tree equally desirable. The oaks, though of slower growth 

 at first are by far the noblest and most long-lived trees. The red, pin and 

 scarlet oaks are the three best species for street purposes. The red oak is faster 

 growing and least fastidious in its soil and moisture requirements. The pin 

 oak is most beautiful when its low pendulous branches are disturbed as little 

 as possible and when its roots can get plenty of moisture. The tree is there- 

 fore best adapted for suburban sections. The scarlet oak is worth the trial 

 for its persistent and brilliant foliage. The ginkgo has demonstrated its 

 adaptability to poor soils, to unfavorable city conditions and its resistance to 

 insects and disease. It should be tried to a greater extent for street planting 

 than it generally is. The English elm is another tree doing well in many 

 large cities. 



There are a number of trees that are planted for their admirable qualities 

 of either form, color or beauty of their flowers, but requiring special favorable 

 conditions and care, they should be chosen with a greater degi-ee of hesitancy 

 than the above and planted preferably in the suburban sections rather than 

 in the heart of the city. The iiriucipal of these are the sugar and red maples, 

 European linden, horsechestnut, American elm and tulip tree. 



The sugar maple has a symmetrical form and combines many shades of 

 color in the fall, but requires plenty of moisture. In the vicinity of New York 

 city, the trees of this species planted in the heart of the city are rapidly dying 

 oflE and there is no other cause attributable for this condition except the exces- 

 sive evaporation from the leaves against the meagre quantity of moisture taken 

 in by the roots from the impoverished street soil. 



*The red maple and the linden are both moisture-loving trees, and the 

 latter is a favorite food for insect pests. The European linden is the better 

 tree for street planting. The American linden grows very straggly in the 

 vicinity of New York though it seems to do better further south. The horse- 

 chestnut prefers a rich soil and is subject to a fungus disease, which discolors 

 its leaves causing them to drop in midsummer. It is also a common victim 

 of "slime flux," a disease that causes the flow of sap from crevices in the trunk. 

 The tree is used extensively abroad for street planting, but for reasons just 

 stated, should be used more sparingly in this country. The elm has the noblest 

 form of all our shade trees, but should be planted on wide avenues, in suburban 

 sections where it can find a deep, rich, moist soil and plenty of unvitiated air. 

 The tulip tree compares favorably with other species in form and attractive- 



