Arboriculture & Urban Forestry 32(2): March 2006 81 of the most practical solutions is the selection and planting of trees with mature heights compatible with overhead electric lines. This solution can improve the appearance of the land- scape, prevent safety hazards, improve electric service reli- ability, and reduce line-clearance expenses for utility compa- nies and their customers. A survey conducted in Pennsylva- nia, showed high approval by residents for the removal of large trees that interfered with utility lines (Flowers and Ger- hold 2000) and replacement with smaller-growing trees that had been trialed in Pennsylvania landscapes (Gerhold 1985, 1999a, 1999b, 2000). In 2000, the Virginia, Municipal Tree Restoration Program (MTRP) was started. It is a partnership representing a state agency (Virginia Department of Forestry), educational insti- tutions [Virginia Tech’s Hampton Roads Agricultural Re- search and Extension Center (HRAREC) and Community Design Assistance Center; Blue Ridge Community College], electric utility companies (Allegheny Energy, Appalachian Power, Dominion Virginia Power, Rappahannock Electric Cooperative), a nonprofit organization (Scenic Virginia), and interested municipalities (including Abingdon, Arlington, Chesapeake, Danville, Luray, Waynesboro, and Winchester). Initially patterned after an MTRP started in Pennsylvania in 1987 (Gerhold 1999c), the major goals of Virginia’s MTRP are • To increase the general public’s awareness of potential tree/utility conflicts. • To increase recognition of tree/utility problems by mu- nicipal tree managers. • To increase removal of utility-unfriendly trees by mu- nicipalities. • To identify utility-appropriate trees by research and field trials. • To increase availability of utility-appropriate tree species in the nursery trade. • To increase awareness of potential tree/utility conflicts in new plantings by developers, city planners, and site plan reviewers. To help achieve these goals, MTRP members decided that a series of utility line arboreta should be developed across Vir- ginia to trial and showcase utility-compatible trees. MATERIALS AND METHODS In fall 1994, a demonstration area designated as a utility line arboretum was started at Virginia Tech’s HRAREC in Vir- ginia Beach, Virginia (USDA Hardiness Zone 8a). The ob- jective in establishing this arboretum was to evaluate and showcase small trees and large shrubs compatible with over- head utility lines. Surveys and literature and Web searches were conducted to identify desirable plant characteristics and to develop a list of trees for initial evaluation (Appleton et al. 1997). Development of the arboretum served as a student’s independent study project in Virginia Tech’s extended- campus Master of Science in Horticulture program (Appleton and French 2003). To provide overhead lines for height reference, Dominion Virginia Power (then Virginia Power) erected three poles and two multi-line spans of uncharged electric lines totaling 91 m (300 ft) at heights averaging 7.6 m (25 ft) and 9.1 m (30 ft) above the ground. The first row of trees was established directly under the lines, with plants installed on 4.5 m (15 ft) centers (total of 20 plants per row). Additional rows were then added parallel to the initial row, 4.5 m (15 ft) apart. Planting beds were prepared by spraying a 1.5 m (5 ft) wide band with glyphosate (Roundup; Monsanto, St. Louis, MO) to kill existing vegetation. Plants were installed following Virginia Tech tree and shrub planting guidelines (Appleton and French 1996). Entire rows were then mulched with 5 to 7.5 cm (2 to 3 in) of wood chips (recycled from local utility line clearance) to suppress additional vegetative growth. De- tails of items and costs associated with developing a similar utility line arboretum are listed in Table 1. All small trees [averaging 1.2 to 2.4 m (4 to 8 ft) tall] and large shrubs [averaging 0.6 to 0.9 m (2 to 3 ft) tall] planted in 1994 and 1995 were obtained from local retail and wholesale nurseries. Due to financial constraints, only one tree or shrub per species was planted to maximize the number of plants that could be purchased and evaluated. Included in the initial planting were two trees with mature heights over 15.2 m (50 ft), one centered under each of the two line spans. These two trees, a red maple (Acer rubrum) and a London planetree (Platanus × acerifolia), were in- cluded to emphasize the size of trees that should not be planted in or near utility easements. For this study, Dominion Virginia Power’s usual easement distances (generally3m[10 ft] in all directions around distribution lines) were used be- cause there are no set easement dimensions uniformly used by utility companies across the United States. Each of these trees was labeled with a sign explaining that it is an inappro- priately tall tree used for height reference. In 1996, 14 trees deemed appropriate for mid-Atlantic con- ditions were selected and planted from the J. Frank Schmidt & Son Company (Boring, OR) line of Utilitrees™(Appleton et al. 1997). The trees were a donation from the nursery in support of the utility line arboretum concept. In subsequent years, additional trees and shrubs have been added, most being less common plants obtained from mail-order nurseries (Forest Farms, Williams, OR; Klehm’s Song Sparrow Peren- nial Farm, Avalon, WI; Rare Find Nursery, Jackson, NJ; Ro- slyn Nursery, Dix Hills, NY). Tree height has been recorded on a yearly basis, and trees that have exceeded height expectations or that failed to sur- vive or appeared inappropriate (excess litter, suckering, pest ©2006 International Society of Arboriculture
March 2006
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