Urban trees for use under utility lines

Department of Horticultural Science Horticulture Information Leaflet 8616 Revised 11/93 - Author Reviewed 2/99 URBAN TREES FOR USE UNDER UTILITY LINES Thomas G. Ranney, Associate Professor Richard E. В ir, Extension Horticulture Associate M. A. (Kim) Powell, Extension Horticulture Specialist ■ Selecting trees for use under utility lines presents a unique challenge. It is often desirable to have trees that are large enough to provide shade, architectural effects, and ornamental features, all without interfering with overhead utility lines. Below we have listed trees that have a typical mature height of less than 30 ft. In most cases the mature height listed is very optimistic. If growing conditions are not ideal, the mature height can be considerably less than what is indicated. The height of utility lines vary considerably and care should be taken to select trees with mature sizes that are less than the overhead clearance. If possible, it is often desirable to set trees back from the utility lines. In doing so, larger maturing trees (see HIL 8638, Large Trees for North Carolina) can be selected if they are planted at a distance of 4i the diameter of the mature crown from the wires. In certain cases, specific cultivars have been listed below. These cultivated varieties may have particular merit due to exceptional ornamental features or due to a unique form, size, or habit. The hardiness ratings presented conform to the USDA hardiness zone map. Zones 6,7, and 8 correspond roughly to the Mountains, Piedmont, and Coastal Plain regions of North Carolina, respectively. All planting sites are different and no single species is suited for all sites and locations. Consideration should always be given to local soil conditions, occurrence of diseases and insects, microclimate, hardiness zone, and mature tree size when selecting any plant. Maintaining a good diversity of species in any landscape planting will help ensure that insects, diseases, and changing environmental conditions will not, at some point, result in widespread problems. Use of different species of trees for each adjacent block of street tree plantings is a good practice. As a general rule, it is desirable to have not more than 1 0% of the trees in an urban area of any one genus and not more than 5% of the trees of any one species. Although this list includes many desirable plants, it is not all inclusive. Experimentation with new introductions and cultivars is encouraged. Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating. North Carolina Cooperative Extension Service NORTH CAROLINA STATE UNIVERSITY COLLEGE OF AGRICULTURE & LIFE SCIENCES