A FRAMEWORK FOR APPLYING INTEGRATED VEGETATION MANAGEMENT ON RIGHTS-OF-WAY

Journal of Arboriculture, Jan 2005 by Nowak, Christopher A, Ballard, Benjamin D

Abstract. Integrated Vegetation Management, or IVM, is purportedly being used by many right-of-way management organizations across the United States. In many cases, IVM is just a name applied to old management approaches. Yet IVM is more than just a name. It is an in-depth and sophisticated system of information gathering, planning, implementing, reviewing, and improving vegetation management treatments. IVM is used to understand, justify, choose among, selectively apply, and monitor different types of treatments, with an overall goal of eliciting site-specific, ecosystem-sensitive, economically sensible, and socially responsible treatment effects that lead to refined achievement of management objectives. We propose a six-step system to IVM that can act as a framework of activities to aid managers and other related stakeholders in communicating, organizing, and conducting IVM business. Each step produces information that must be integrated into the management system. Our six-step system is consistent with Integrated Pest Management and other IVM-like systems developed in forestry and agriculture. We present an IVM system with some unique perspectives and ideas from the literature, and incorporate information from and experience with the electric utility industry.

Key Words. Right-of-way; vegetation management; management systems; powerline corridors; electric transmission lines; pipelines; highway; railroad.

Rights-of-way (ROWs) can be generally defined as units of land used for transportation. As such, ROWs provide many goods, values, and services important to society. Production of values and services can occur from the ROW itself via the act of transport, such as with the movement of people in cars, trucks, and trains. Benefits of ROWs can accrue from the movement of goods, such as gas, oil, and electricity-these goods hold the benefit, and ROWs are a means of transmitting or distributing them to a place where the direct benefit is secured.

All ROWs are managed with a general goal of providing sale and reliable transport. Managers endeavor to meet this goal by creating corridors that exist in narrowly defined technical and environmental states. In almost all ROW scenarios, active management is needed to create specific vegetation and related environmental conditions. On electric transmission line ROWs, the selective removal of tall-growing trees and promotion of low-growing, relatively stable plant communities composed of grasses, forbs, and shrubs is the common approach to vegetation management. Tall-growing trees can cause unsafe conditions and shortfalls in reliability by growing into or near the wire conductors. These trees act as conduits for electricity, causing ground-fault disruptions in transmission. ROWs fully occupied by low-growing plants have been shown to produce safe, reliable, cost-effective transmission of electricity, primarily because, over the long-term, they result in a minimal amount of undesirable trees (Egler 1953; Niering 1958; Nowak and Abrahamson 1993; Finch and Shupe 1997; Jackson 1997).

Tree seeds and seedlings are consumed by small mammals that find suitable cover in the low-growing plants. When trees do become established, their growth and development are minimized by interference from the low-growing plant community (Bramble and Byrnes 1983; Hill et al. 1995; Bramble et al. 1996). Reduced and minimized tree populations lead to a reduction in management inputs. Herbicide use can be halved when this selective vegetation management approach is used, compared to other less-discriminate approaches such as broadcast spraying (Nowak and Abrahamson 1993; Finch and Shupe 1997). In addition to providing desirable corridor conditions for the transport of electricity and minimization of management costs, ROWs managed for complex, low-growing plant communities provide a wide variety of environmental values, benefits, and services, particularly associated with wildlife (Nowak 2002; Yahner 2004).

The idea of selective tree removal to manage powerline ROWs was first proposed 50 years ago (Egler 1953; Niering and Egler 1955; Niering 1958), with numerous, subsequent re-propositions (Niering and Goodwin 1974; Dreyer and Niering 1986; Niering et al. 1986; Bramble et al. 1990; Nowak and Abrahamson 1993). Over the past five decades, herbicides have been presented as both the optimum way of controlling the pest (the tall-growing trees) and a treatment that minimizes its own use in the long run, as explained above.

The selective vegetation management approach has been a part of New York State regulations since 1980 (Nowak and Abrahamson 1993; Jackson 1997; McLoughlin 2002). Other states and regions have also adopted this approach to vegetation management (Van Bossuyt 1987; Daar 1991; Bramble and Byrnes 1996; Wells et al. 2002).

In the 1980s, the selective vegetation management approach was first compared to Integrated Pest Management (IPM), as it was clear that the selective control of tree pests followed the core precepts of IPM-"prevention" and "integrated control" (sensu Stern et al. 1959). Because it was not clear that all of the precepts and principles of IPM applied to vegetation management on powerline corridors, and, given that for many people it is difficult to view trees as "pests," the phrase "Integrated Vegetation Management" was coined (Jackson 1997; McLoughlin 2002). Efforts to apply IPM in other plant systems have resulted in similar phrases to describe vegetation management systems, such as "Integrated Weed Management" in agriculture (Swanton and Weise 1991) and "Integrated Forest Vegetation Management" in forestry (Wagner 1994).