Designing and implementing an integrated vegetation management (IVM) program is critical for the long-term success of a utility vegetation management (UVM) program. Properly maintained rights-of-way are essential for the safety of customers and workers, but it is much more than that.
Today, more than ever, utilities are focusing on minimizing vegetation-related outages while providing access to power lines for the inspection and maintenance of electric transmission and distribution facilities, and for the timely restoration of service during emergency conditions. IVM enables utilities to minimize interruptions caused by vegetation while maintaining a harmonious relationship with varied land uses and the environment.
ANSI A300 Part 7 - Integrated Vegetation Management best management practices defines IVM as “a system of managing plant communities in which managers set objectives; identify compatible and incompatible vegetation; consider action thresholds; and evaluate, select and implement the most appropriate control method or methods to achieve those objectives.”
Vegetation management recommendations for electric facilities include combinations of manual, mechanical, cultural, biological and chemical methods to transpose existing vegetation into relatively stable communities of low-growing grasses and broadleaf species. The choice of treatment options is based on ensuring the health and safety of both the worker and the public while taking into account the environmental impact, treatment effectiveness, site characteristics and economics.
IVM Knowledge and Experience
Developing an effective IVM program requires knowledge and experience in IVM as well as in-depth knowledge of applicable federal, state and local regulations. Of course those who are developing IVM programs have access to applicable industry standards and best management practices, including the ANSI A300 Part 7 - IVM best management practices.
Anyone can cut a tree down or mow a right-of-way, but a professional vegetation manager adds immense value by creating a sustainable plant community that will reduce long-term maintenance costs and improve reliability. In short, good IVM programs enhance your rights-of-way.
Vegetation managers have many resources available when developing and implementing an IVM program. They call upon foresters and arborists who have years of experience and expertise with all the tools of IVM and have implemented many successful projects. Look for UVM contractors who have experienced staff that can assist in the development of an IVM program. Chemical supplier representatives often have similar expertise and experience working with utilities developing IVM programs. Vegetation managers also should consider reaching out to non-utility vegetation managers who have experience with IVM and herbicides, such as those working for state, county and federal entities, and to professional applicators with experience in utility, forestry or roadside vegetation management programs.
Technical knowledge is only one part of the skill set that is necessary to develop an IVM program. Strong communication skills are equally important. An IVM program that does not include a communication plan and ignores the need for effective internal and external communication is doomed for failure.
Elements of an IVM Program
Part of the value that professional vegetation managers bring to the development of an IVM program is their understanding of the important steps that must be taken and questions that must be answered during each phase of the program.
Developing objectives. What is your desired end state?
Identifying compatible and incompatible vegetation. Are they considered noxious or are they protected?
Setting action thresholds. What is the optimal timing of implementing a control method, and does this vary by landowner, land rights or other criteria?
Developing criteria to evaluate and select appropriate control method(s). How do you decide what and when?
Implementing control method(s). You've selected your control method, now what?
Evaluating control method(s). How do you know you have been successful and when do you make that determination?
Recordkeeping. Recordkeeping is crucial if you want to make adjustments to your program.
Vegetation Treatment Methods
The tools of IVM are manual, mechanical, chemical, cultural and biological. A plan should include descriptions of each technique, with examples of each technique and descriptions of where each can be used.
Chain saws, pole saws, machetes, string trimmers, McLeods and chippers are used for manual vegetation management. Chain saws, pole saws and machetes are used to remove woody species such as oaks, conifers and brush greater than one inch in diameter. The string trimmers and McLeods are used to clear grasses and smaller woody species. Manually cleared vegetation is lopped and scattered, piled or chipped, depending on fuel hazard, soils and access.
Large mechanical equipment is either rubber-tired or track-equipped. Mechanical mowing is generally used for the initial control of dense woody species. Mowing occurs every two to five years in areas where herbicides are not a viable option. Rubber-tired equipment is used to cut and chip woody species where slopes are less than 25%. The rubber-tired machines also can be used along improved road surfaces such as asphalt or gravel. Track-mounted equipment is used on unpaved surfaces with up to a 35% slope. These large mechanical brush mowers can be used to cut and masticate woody plants to within 12 inches of the ground surface, which reduces fuel hazard. Mechanical treatment usually results in vigorous resprouting of woody species.
There are downsides to mechanical vegetation. A common public misconception is that manual and mechanical methods (chain saws and mowing) are safer and have less environmental impact than the use of herbicides. Often overlooked are the environmental and safety concerns associated with repeated cutting of vegetation. These concerns include soil compaction from heavy equipment, damage to sensitive wetland areas, worker and environmental exposure to petroleum products (which are more toxic than many herbicides used for right-of-way maintenance), the potential for physical injury from sharp tools and equipment, the increased fire risk and the repeated, significant alteration of potential wildlife habitat.
The goal of an IVM system is to manage vegetation and to balance benefits of control, public health and safety, environmental quality and cost.
Repeated cutting or mowing of vegetation perpetuates the growth of incompatible vegetation because of the biological response of resprouting. When a stem is cut, multiple sprouts can grow from the severed stump or the root system (so-called “root-suckering”). These sprouts are fast-growing because they are fed from a root system that is already well established. A repetitive cycle of cutting and sprouting results in an increasing density of large-stature species. The combination of mechanical and manual methods with the selective use of herbicides is very effective in controlling resprouting tree and woody brush species that present problems for the access and maintenance of electric transmission facilities.
These are exciting times with the current and new herbicides available to utility vegetation managers. In the past, treatments were in pounds or gallons per acres; newer herbicides are usually only ounces per acre. The herbicides also are tested by the Federal Environmental Protection Agency to demonstrate how quickly they break down in the environment. Herbicides can help you selectively create a sustainable vegetation type that can be recognized as environmental stewardship by many conservation organizations.
There are a variety of application options by which to apply herbicides:
- Foliar and Contact Application Methods
Foliar backpack applications can be selective or non-selective, depending on the type of herbicide and the application method. Broadleaf herbicides can selectively control broadleaf weeds such as yellow star thistle (Centaurea solstitialis) without affecting desirable grasses. Even non-selective herbicides can be used for selective control through the use of low-volume, directed backpack applications or by timing the application so that the desired annual species have already produced seed.
Basal stem treatments are another selective contact treatment. Basal stem treatments are usually made using backpack sprayers. Herbicide is mixed with a methylated seed oil (MSO) carrier to allow adequate bark penetration and is applied to the lower two feet of a woody plant. MSOs are oils derived from vegetables like soybeans. Basal stem applications have a longer application season and can provide good control from March through November. Dormant applications have low visibility since the target species never leafs out in the spring and there is no brownout.
Hack and Squirt is another selective contract treatment. Using a hatchet, or similar device, cuts are made at a downward angle completely through the bark and cambium at approximately equal intervals around the tree. The herbicide is then applied using a squirt bottle, syringe or similar device to the cut or “hack.” The application is made so that the solution does not run out of the cut.
Cut-stump treatments are used to prevent woody species from resprouting. After trees and brush are cut with a chain saw or loppers, the stump is treated with herbicide. Most cut-stump treatments can be made year-round.
Injection is an application method in which capsules containing herbicide are injected into the woody cambium, and the herbicide gradually translocates to the roots and stems.
- Soil Active Application Methods
Soil active herbicides like hexazinone can be either selective or non-selective.
Selective soil active herbicides can be used to control undesirable broadleaf species while maintaining desirable grass species. These herbicides can be an important part of your program to control invasive weeds. Soil active herbicides also can be used selectively with application techniques such as spot gun that direct the herbicide only to the targeted species.
Non-selective soil active herbicides are generally used where bare-ground conditions are required for six months to one year. These non-selective herbicides are usually applied to bare-ground conditions in the fall or early winter and prevent seedling germination.
Cultural methods manipulate the vegetation and encourage compatible species while discouraging incompatible species. These include seeding, mulching or using the right-of-way for compatible agriculture crops, golf courses and parks. The long-term success of the well-known wire zone/border zone right-of-way management strategy developed by Dr. Bramble and Dr. Byrne relies heavily on developing a right-of-way plant community that is resistant to invasion by trees species. Developing a tree-resistant plant community requires first removing the incompatible and undesirable plant species, and then using selective techniques to allow compatible and desirable species to dominate.
Biological methods can incorporate the use of goats, sheep or cattle. While these grazing animals are a tool, they usually do not control all the re-sprouting species and can require multiple entries within a growing season. In some cases, they will only graze less preferred species when crowded, which can create undesirable impacts. It also may be difficult or impossible to prevent them from grazing compatible, desirable and threatened, endangered and protected species. These animals can be used in conjunction with other techniques to increase efficacy.
Implementation of an IVM Program
Before implementing an IVM program, a vegetation manager must communicate with internal stakeholders and build support for the IVM program. This is particularly important if the utility has not included herbicides as part of its UVM program in the past. Sometimes it is the misinformation from within the utility and sometimes it may be fear of controversy and usually a lack of knowledge or experience. The reality is that almost all utilities already use herbicides to maintain substations, power plant sites and urban landscapes around offices.
A Good Communication Plan
The need for a good internal and external communication plan cannot be overemphasized. The utility vegetation manager understands the need for maintenance activities, but media, governmental representatives, upper management and environmental specialists within the utility might not. You may even think that all internal stakeholders will support your IVM program. Spend time determining who has concerns with the plan and actively reach out to those stakeholders.
Your communication plan is to educate and build support and respect for the IVM plan within the utility while building support with external stakeholders. Utilities have tried to implement IVM programs without a good stakeholder communication plan in place and have suffered the consequences. It can take years to recover the support and respect for a program that ignored internal stakeholders.
Reaching out to external stakeholders can help build community support for the plan. This is again an opportunity to educate cities, counties and agencies on the reasons for your plan and the benefits for the community.
Building partnerships internally and externally will help build support for your right-of-way program and also help you manage issues as they arise. Reach out to your upper management, news representatives, environmental specialists and governmental representatives. Demonstrate your technical skills and your communication skills, and you will gain their confidence. Prepare standby statements and FAQs to help them help you be successful.
External partnerships can pay big dividends. State and county departments of transportation use herbicides routinely to control vegetation along roads and can be helpful in documenting other programs that use herbicides in your area. Many of the manufacturers and distributors can provide more contacts in your area and guide you through any regulatory challenges.
Once you've built support both internally and externally, you're ready to think about how you're going to get the real work done on the ground. Will you use utility employees or contractors? Do you have people on board with the proper qualifications? What about pesticide applicators licenses? Can they communicate? Can they explain your IVM program and answer concerned neighbors' questions? If they can't, you might want to reconsider your strategy or risk failure.
There are many key messages to be communicated, but do the people communicating with interest groups know them? The messages and the delivery should be direct and positive:
We are using IVM best management practices.
Our goal is to create a sustainable vegetation type of grasses and low-growing shrubs.
We are using EPA-approved herbicides and professionally trained applicators.
The vegetation will provide a diverse habitat for wildlife, plants and pollinators.
Our program is designed to reduce visits to your property to maintain the right-of-way.
The success of an IVM program requires a comprehensive, well-executed plan. Utilities would do well to call upon professional vegetation managers to develop an IVM plan and trained professionals to implement the plan if they are to reap the benefits for their utilities, for utility customers and the public at large.
Editor's note: This article was independently written by Nelsen Money, as contracted by the editorial director of Transmission & Distribution World. Money, president of NRM-VMS Inc., has more than 37 years of utility vegetation management experience. He is an ISA Certified Arborist/Utility Specialist, California Licensed Professional Forester and California Licensed Pest Control Advisor. He is past president of the Utility Arborist Association, and has been a speaker and writer for many professional organizations and publications.