To operate and maintain the transmission lines safely and reliably, VELCO must clear the land under and around the lines. Using approved plans, and under supervision of VELCO personnel, crews carefully remove trees and brush. Brush is chipped in the right-of-way and logs are windrowed, (stacked in a pile along the edge of the right-of-way) for the landowner’s use. The clearing is performed to minimize disturbances to streams, wetlands, and other sensitive areas. Selective Clearing occurs in the specific sections of the right-of-way designated for special vegetative treatment. These areas are those immediately adjacent to stream crossings, wetlands, highways, and other areas with special environmental or aesthetic concerns. In these areas, trees that will not grow to a height of more than 12 feet are allowed to remain to the greatest extent possible.
Trees along the outside of the corridor are also assessed to determine their ability to have an impact on safety and reliability in the event the tree fails and falls into the line. These are referred to as danger trees, but even if identified as such, not all danger trees that have the potential to hit the line are removed. Danger tree removal is determined by criteria that include species, soil, health and growth pattern conditions.
Following construction, the right-of-way is maintained in such a way as to respect the environment and ensure a reliable flow of electricity along the transmission lines by following a strict program of vegetation management. VELCO selectively controls vegetation growth in a transmission line right-of-way in a manner that maintains the integrity of the landscape. The resulting right-of-way provides an ideal habitat for many species of wildlife that otherwise would not be able to flourish in Vermont’s environment.
This vegetation-control program is an Integrated Vegetation Management Program which calls for the use of best management practices over a four-year cycle. The plan is re-evaluated every four years to account for changes in vegetation growth in the rights-of-way, and improvements in vegetation management techniques.
Prior to vegetation management work, rights-of-way are patrolled and management techniques are selected. Integrated Vegetation Management techniques are determined by safety, health, environmental concerns, efficiency, and economic considerations. Methods used to maintain the vegetation include mechanical clearing with equipment such as chainsaws, brush saws, or mowing machines and, in some areas, the selective use of herbicides.
All grasses, herbs, most shrubs and some low-mature-height trees are normally considered desirable and encouraged to grow. Undesirable tall growing species of trees are removed, allowing the low growing desirable species of trees and shrubs to edge out the undesirables. Trees that will grow to a height of more than 12 feet must be selectively controlled or removed to avoid interference with the line and maintain accessibility to the line for maintenance operations.
The herbicides used to control the vegetation are tightly controlled. Each year, VELCO must receive a permit from the Vermont Department of Agriculture, Food and Markets that reflect the latest scientific analysis before it can begin herbicide applications on the rights-of-way. Herbicide applications are made using low volume techniques to individual undesirable species of trees by Vermont Certified Applicators. Field inspections by the Vermont Agency of Agriculture ensure regulations are being followed. VELCO supports this control measure as the most environmentally sound approach. Landowners, nonetheless, may require VELCO to not use herbicides if they so choose.