Vegetation Management

Integrated Vegetation Management (IVM) is a system of managing plant communities that considers a combination of methods to control undesirable vegetation and includes biological, cultural and physical (e.g. mechanical and manual) methods of control.  The Block Island Power Company will not utilize any chemicals or herbicides in its management activities.

Our program promotes sustainable plant communities which are compatible with the electric facilities and discourages incompatible plants (i.e. plant species which at maturity will attain a height of greater than +/- 15 feet tall) that may pose concerns including safety, access, fire hazard, electric service reliability, emergency restoration, visibility, regulatory compliance, environmental and other specific concerns.

Important benefits of our Vegetation Management Program include:

• Worker and public safety
• Increased visibility and access along rights-of-way
• More timely and less costly outage restoration
• Safer working conditions for line workers and line clearance contractors
• Improved species selectivity
• Long-term control of right of way brush and trees
• Promotes stable plant communities
• Supports natural (biological) control
• Promotes bio-diversity among plants and wildlife
• Only feasible control method for invasive species
• Most efficient and economical control

Determination of Vegetation Management Needs

The Block Island Power Company has established a preventative maintenance strategy, identifying an appropriate routine maintenance cycle, identifying necessary funds to complete maintenance on the desired cycle, determining scheduling units, prioritizing scheduling units and completing routine maintenance systematically and on the desired cycle.  Vegetation maintenance records, service interruption data, line worker reports, line patrols and member-customer input all contribute to assigning priorities for vegetation maintenance each year.

There are several factors we must consider when evaluating vegetation management needs.   These include the frequency of service interruptions, vegetation density and characteristics, time elapsed since last treatment and member-customer requests.

Vegetation Maintenance Cycle

Block Island Power Company has established a target of attaining a five-year vegetation maintenance cycle on its distribution rights-of-way.

Undesirable Vs. Desirable Vegetation

Not all trees identified on Block Island are classified as incompatible with electric utility lines, however most that grow to over 15 feet tall are classified as incompatible. They are generally moderate to fast growing species, reaching mature heights that threaten the power lines.  Immature trees (less than 4 inches in diameter at breast height and with the capability to exceed 15 feet in height) are defined as incompatible target brush.

Although immature brush does not pose an immediate threat to system reliability or safety, allowing it to mature can increase maintenance costs and impede or prevent accessibility to electric facilities.  Aggressive incompatible target brush species control is crucial in limiting our future vegetation control workload and cost increases.

While individual healthy trees existing within rights-of-way may be pruned and maintained in order to avoid contact with conductors, our long-term goal will be to eliminate them when economically feasible. Future planting of these tree species within the rights-of-way is strongly discouraged.

The most common reason for pruning an incompatible tree rather than removing it is landowner or tree warden request.  This may be because of the aesthetic value, or because of its value as a shade tree or as a screen from a highway.  Apple trees, due to their value as wildlife feed, will be pruned for maximum clearance without jeopardizing their survival and removed only when necessary.

Not all vegetation found in our rights-of-way is undesirable.  There are many low-growing plants and shrubs such as lilac, serviceberry, dogwood, hawthorns, honeysuckle, etc., which can be compatible with utility lines.  In wetlands and boggy areas, species such as speckled alder and pussy willows, as well as cattails, ferns and many other low growing plants and shrubs are quite compatible.

Retaining or encouraging the growth of low-growing desirable vegetation will help to suppress the growth and density of less desirable species.  While shrub growth will not eliminate the encroachment of tree species, it will compete with the other species for nutrients, light, and space.

Significant shrub growth is not retained in the area immediately surrounding pole locations or directly under the conductors.  These areas must be kept free of obstruction to facilitate access to the poles and create an open access for line workers.  This is especially important for any plant species bearing briars or thorns, as they threaten the line workers safety.

Off Road Vegetation Maintenance

Generally involves the cutting of all incompatible trees and target brush (up to 10 feet on each side of the center of the line) to ground level, as well as proper pruning of all branches growing towards conductors and removal of any/all trees, which cannot be properly pruned to provide adequate clearance.

Off Road Vegetation Maintenance

Generally involves the cutting or pruning of all incompatible trees and target brush (within 15 vertical feet below the conductors, 10 feet vertical feet above the conductors and at least 6 horizontal feet from the closet conductor) as well as proper pruning of all branches growing towards conductors and removal of any/all trees, which cannot be properly pruned to provide adequate clearance. Our goal is to provide adequate access to the wires by our bucket trucks.

Hazard Tree Removal

Involves the removal of trees, which due to size, location and/or condition, that pose an immediate threat or have a potential to damage the conductors or structures within the next five years.  These trees will be removed regardless of distance from the center of the pole line.

Minimum Tree-to-Conductor Clearances

A minimum of 6 feet of clearance on each side of the outside conductors, 15 feet of clearance for all branches under the power lines and 10 feet from branches that overhang the conductors must be achieved.  Additional clearance is necessary on branches that could bend (due to snow or ice loading) or break and contact the conductors below.

These are the minimum required clearances.  Individual tree location, health, species, and growth rate must be considered when determining appropriate/acceptable clearances.

Disposal and Clean Up Procedures

Brush, branches and woody debris from pruning and removal operations along roadsides and within 100 feet of house sites will be chipped and mostly hauled away unless the landowner wants the chips left behind. In all other areas, brush will be moved away from the poles, out from under the conductors and windrowed (placed in a long, low heap or pile) off to the side. Our goal is to leave the rights of way in a condition that the landowner is satisfied with and allows for future good access to the line.

Trees, which have been cut remain the property of the landowner and disposal of usable wood will be coordinated with the landowner.

Stonewalls

The stonewalls on Block Island are an important part of the Island’s history with many dating back to the 17th century. Extra caution will be taken when working near stonewalls to prevent damage. Minor displacement of rocks shall be repaired immediately. More significant disturbance or damage shall be reported immediately.

Customer Notification

The Block Island Power Company will hire a Worker Planner to prescribe all vegetation management needs and will coordinate the work with the Town of New Shoreham Tree Warden and the landowners. The Contractor has the primary responsibility for contacting property owners prior to the commencement of vegetation management work.  Personal contact will be made wherever possible and a notification hang tag will be left at all residences along the rights of way scheduled for maintenance activities.

Where personal notification has not been made, maintenance activities will not take place for a minimum of 2 weeks following the placement of a notification hang tag.  If 2 weeks have passed and the member has not made contact with the foreperson identified on the hang tag, maintenance activities will take place without any further notice.

A reasonable effort will be made to identify property owners at locations where there is not a nearby residence.

Staff Qualifications and Guiding Work Standards

The Block Island Power Company requires the Work Planner and at least one member of each Tree Crew to be a certified Utility Arborist. All cutting and pruning methods will comply by the ANSI A300 Standards.