302 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



They are also of value in removing vegetation which harbors destruc- 

 tive insects. Nevertheless each plant, each insect, demands a separate 

 decision. As in the field of human medicine, there is no panacea 

 for all diseases. From another point of view, ornamental 'values rank 

 higli in roadside management, and most State departments now have 

 their own landscape divisions, often involved in planting shrubs in 

 strategic places along the roadways. It has sometimes seemed in- 

 consistent therefore to find miles and miles of laurels, viburnums, 

 azaleas, blueberries, cornels, and other briglitly flowering shrubs 

 destroyed. 



Finally we have the wildlife values. The question of the preserva- 

 tion or destruction of wildlife cannot be decided arbitrarily. Each 

 highway has its own wildlife problems. On major arteries and near 

 the centers of population, big game quite obviously should not be en- 

 couraged because of traffic hazards. In suburban areas, song birds 

 are apj^reciated and enjoyed by many groups of residents. It is 

 known that most of these birds increase in number in the crop borders 

 and roadside thickets. Yet it is these thickets that are often destroyed 

 by indiscriminate spraying. The same habitats foster grouse, pheas- 

 ant, quail, and other game animals. Most wildlife inhabits "edges" 

 or "borders" — combinations of vegetation types, not solid forest or 

 wide-open grasslands. To preserve these wildlife habitats, we must 

 also preserve the roadside thickets. 



RAILROAD RIGHTS-OF-WAY 



The situation along railroads is in many ways similar to that of 

 the roadsides. The vegetation to be treated parallels a high-speed 

 transportation route, so that the procedure can be highly mechanized 

 and uncostly. The land can bo segregated into a series of parallel 

 belts, for each of which the fundamental needs are diflferent. The 

 stone ballast surrounding the rails and ties must remain free of all 

 vegetation, to insure quick drainage. Likewise, strips a few feet wide 

 on each side of this should remain clear of plants. The rest of the 

 right-of-way, often involving side strips up to 50 feet wide, can 

 remain in plants, but of a low-growing variety. For lines using 

 steam locomotives, the fire hazard is a factor. 



POWER AND TELEPHONE RIGHTS-OF-WAY 



The cross-country rights-of-way of these public utilities differ in 

 important respects from the two preceding. Usually, the only routes 

 they parallel are those of the crow. Sometimes, as in southern West 

 Virginia, the lines leap from crest to crest, and progression under them 

 is all but impossible, for either man or mule. 



Telephone toll lines are generally only 40 or 50 feet wide. Power 

 transmission lines are usually 100 feet wide but may be as much as 



