STREET TREES. Itis always desirable both for the shade and for the appearance, and usually possible, to have the streets, at least those devoted to residences, lined with trees on each side. Although trees in the streets have an important sanitary and aesthetic value, opinions differ regarding the proper responsibility for them. One view vests all right and title to the tree in the owner of the property before which it stands; and the other asserts that the trees belong to the city at large and that the individual has no more right to the tree in front of his property than has any other citizen. In the first case, the planting of the tree, its kind, position, and care depend upon the public spirit of the property holder; and as a result the street presents a motley, straggling appearance often with no trees where they are most needed for the best general effect. Without some degree of public control, it is impossible even to approximate the best results of tree planting; but fortunately the number of cities is rapidly increasing in which the street trees are under the control of the municipal authorities.
In planning a system of streets, the location of the trees should be definitely provided for. They should be located in the grass plats between the sidewalk and the edge of the pavement, and at a sufficient distance from both the sidewalk and the pavement that there will be no danger of the roots lifting either. The trees should be spaced in the row so as to permit each when fully grown to spread to its natural dimensions, which usually requires a space of 25 to 40 feet. Not infrequently trees are planted much too close—particularly in the fertile and originally treeless prairies of the Mississippi Valley;—and are left to crowd each other and to prevent a symmetrical growth. In planting trees, it is well to alternate those of rapid growth with those which mature more slowly; and then as the latter increase in size and demand more room, the former, having served their temporary purpose, can be removed. Increased stateliness, impressiveness, and charm is secured if the trees, at least the permanent ones, on any one thor oughfare are of one variety. Different streets can have different kinds of trees, since in nearly all cities there are a large number of suitable varieties available.
In most states there are one or more cities that have obtained—either officially or by volunteer civic-improvement societies—valuable experience as to the varieties best suited to the environment, from whom data can doubtless be obtained by those desiring information concerning the kind of trees to plant in the streets of any particular city.
The following are the requirements for a street tree adopted by a commission of experts for Washington City.* "1. A somewhat compact stateliness and symmetry of growth. as distinguished from a low spreading or pendant form, so that the stem may reach a sufficient height to allow free circulation of air below the branches. 2. An ample supply of expansive foliage of bright early spring verdure, and rich in the variety of colors and tints assumed during autumn. 3. Healthiness, so far as being exempt from constitutional diseases, as well as by maladies fre quently engendered by peculiarities of soil and atmosphere im purities. 4. Cleanliness, characterized by a persistency of foliage during the summer, freedom from fading flowers, and exemption from the attacks of noxious insects. 5. It should be easily trans planted, of moderately vigorous growth, and not inclined to throw up shoots from the root or lower portion of the stem. A tree of extremely rapid growth is generally short-lived. 6. The branches should be elastic rather than brittle, that they may withstand heavy storms; and lastly, there should be no offensive odor from foliage or flowers." Of course, no tree planted amid the artificial conditions found in a large city will fully meet such rigid requirements. In 1872, at the commencement of systematic tree planting, the above com mission recommended the following list of trees. The Silver Maple (Acer dasycarpum), the American Linden (Tilia americana), the European Sycamore Maple (Acer pseudo-platanus) and the Amer ican Elm (IJlmus americana) are thought to fill all the above requirements when not subjected to the attacks of insects. The Tulip Tree (Liriodendron tulipifera), Sugar Maple (Acer saccha rinum), Sweet Gum (Liquidamber styraciflua), and the Red Maple (Acer rubrum) are the most beautiful of trees, their only drawback being that of not growing freely after transplanting. The Nor way Maple (Acer platanoides), the Negundo (Acer negundo), and the American Ash (Fraximus americana) are recommended for certain places. The Button-woods or Planes (Platanus occi dentalis and Platanus orientalis) are rapid growing, and for wide avenues are effective trees.
As a result of twenty-five years' experience, the trees are ranked as follows: * "Silver Maple, Norway Maple, and Eastern Plane side by side in the first rank; then the Ginkgo, and Western Plane; and last American Linden, Oak, and Sugar Maple."