T&D World Magazine

Vegetation Management Research

In the last issue I argued that every utility using integrated VM should have both research and demonstration plots. I should clarify that when I say research I mean work where outcomes are statistically compared and analyzed. You want results that are statistically significant and valid and therefore, not easily challenged.

So what kind of research should a utility undertake for VM?

Research can be used to establish the efficacy and cost-effectiveness of the right of way treatments the utility uses, be that mowing, grazing or any number of herbicides. The research should try to find what treatment, which falls within acceptable environmental standards, provides the longest maintenance free period. There are two things which need to be measured: the control of existing and targeted stems and the amount of regrowth. Typically, herbicides which do not effectively control the treated stems, will also permit considerable regrowth and consequently, will not fare well in establishing an effective maintenance free period. For the evaluation of herbicide efficacy the control treatment would typically be some form of cutting with no herbicide follow-up. You can find examples and guidance on evaluating regrowth at http://www.ecosync.com/products.htm. Start with the article titled The Validity of an Estimation of Biomass. For an example of application see the article below that.

Do you have root suckering species? Then one of the things you want to research is the amount of suckers that are generated from every cut tree. I came upon this serendipitously through a stump treating trial. The trial was abandoned when we found herbicides which translocated well were too effective in that not only did they flash-back among clones but even crossed to non-target trees through root contact. The untreated stumps were to be the control and there were two timings for cutting: just after leaf-out, and after leaf drop. This work provided an incredibly powerful answer to why did we use herbicides as opposed to a regimen of cutting. We could state that for every poplar tree cut we got 18 suckers when root reserves were at the lowest level and 64 suckers when root reserves were at the highest seasonal level. We all know that cutting increases the brush density. However, the impact of simply stating cutting increases brush density versus being able to state that cutting will magnify the problem a minimum of 18 times, is totally different. Mind you this data comes from trees that were at a minimum 6” dbh and therefore, had a more extensive root system than smaller trees we would classify as brush. However, who can argue the point unless they have specific data that contradicts the research findings?

Don’t know where to start, what to research? Think of the questions and concerns that landowners and stakeholders tend to raise. What information would be useful to explain or justify your treatment choices? What questions may you need to answer in the future?

Last month I also stated that utilities should have demonstration plots. The demonstration plots are for show and tell. They should be reflective of the results produced by the integrated VM program and ideally you would locate some such plots where they are easily accessible. If you are using herbicides then the demonstration area should show the results of that but also have at least a small area that has been maintained by cutting. Before you take groups out to the demonstration plots, you should have completed the research which establishes the broader environmental impacts of the treatments. This means you should know the difference in species diversity and abundance between herbicide treated rights of way and either areas maintained by cutting or adjacent lands not treated with herbicides. You might also extend this research to evaluate the food and/or habitat value to birds, animals, insects and any biota of specific concern. When you have this data, put together a slide show that provides pictures and key research results. It can be used as an educational tool and may be adequate to address some of the concerns you encounter. But honestly, there is nothing like boots on the ground, standing in the right of way showcasing the environmental benefits of your VM program. While the stakeholder may be impressed by the visual impact don’t expect him to be able to discern the species diversity and abundance. You need to raise this with specific data and to draw attention to species which hold particular value and/or are not found in the control plots.

You may be tempted to save money by relying on the research of others (see Highlights). While work by Bramble, Byrnes and Yahner proves supportive of utilities’ use of integrated VM, you will find it far more effective to have local data, which is corroborated by studies in other geographic areas.

If you have not undertaken right of way or other VM research, what is holding you back? Is it a lack of knowledge of research protocols or statistics? You can hire this expertise. Is it money? If you were to spend ½ of a percent of your VM budget on research, you would be amazed at the wealth of information that would come into your possession. If the utility industry as a whole did this, the impact would be unimaginable.

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