New Diagrams and Applications for the Wire Zone-Border Zone Approach to Vegetation Management on Electric Transmission Line Rights-of-Way

摘要

The wire zone-border zone (WZ/BZ) approach to vegetation management on electric transmission line rights-of-way (ROWs) was formally introduced by Drs. Bramble and Byrnes in the mid-1980s (Bramble et al. 1985, 1986). It is a site-explicit way of dividing the ROW width into three distinct management zones from edge to edge: the border zone, the wire zone, and another border zone (Figure 1). In this classical WZ/BZ approach, the ROW vegetation is managed differently in the two basic zones, purportedly to optimize the safe and reliable transmission of electricity. Herb-grass-forb cover types (low-growing vegetation), which may include some very short woody shrubs (oftentimes all woody shrubs are excluded), are promoted in the wire zone; whereas shrub-short tree cover types (taller woody vegetation) are allowed to grow in the border zones (Ballard et al. 2004; Yahner and Hutnik 2004). The WZ/BZ approach is also touted to ensure that other values are consistently, predictably produced on ROWs, includingaesthetics, wildlife habitat (as exemplified by Bramble, Byrnes, and Yahner's Pennsylvania State Game Lands 33 research; e.g., Bramble et al. 1985, 1986; Yahner et al. 2004), biodiversity, and lower long-term vegetation management costs.