Because utility rights of way create a major visual impact and in fact create permanent changes to the landscape over which they traverse, they often become one of the most highly criticized aspects of utility line construction and subsequent management. This is because we’re directly affecting major natural resources of land, timber, as well as other natural resources. It has been estimated that within the United States alone, there are over 50 million acres of rights of way which is equivalent to an area of land greater in size than all six New England states combined (includes highways, railroads, power lines, telephone, and pipeline rights of way). With the magnitude of such a land base, and the total potential impact which can result from management or mismanagement of these lands, it becomes of utmost importance that management of this land base be maintained at the highest level.
A high level of management cannot be attained unless basic functions of good management are met. Without long-range planning and positive identification of management goals and objectives, efficient management is not possible. Proper R/W vegetation management implies the art of managing vegetation at the lowest long-term costs with due consideration for natural resource values as well as engineering needs.
Field inventories and good records are two basic ingredients of any successful vegetation and/or land management program. Inadequate field inventory data more often than not result in inefficiencies in terms of planning and overall management. Likewise, the lack of an adequate system of records also results in gross inefficiencies in achieving long-term management objectives.
With adequate basic field data, it is possible to maximize environmental quality at reasonable costs and still maintain the integrity of the power line or other utility for which the R/W is being maintained. Factors which must be considered in arriving at decisions regarding management methods and techniques to be employed on R/W systems include:
vegetative cover types
size and density of vegetation
accessibility
terrain
environmental factors
associated land uses
It has been said that the most economic control for unwanted plants is other plants. The elimination of certain plants from a plant community may modify that community favorably or unfavorably and, therefore, the totality of the existing plant communities should be taken under consideration in vegetation management activities. If this is true, it then becomes of utmost importance that those of us responsible for R/W management become aware of the various vegetative cover types which occur on our rights of way so that proper management decisions can be made which will be ecologically sound as well as economically feasible.
The use of the computer in analyzing field data and maintaining adequate records is a basic step toward the management of vegetation at the lowest long-term cost with the highest of conservation values.
Our program of computerized R/W vegetation management evolved from an overall evaluation and review of our transmission line system including a cost analysis of maintenance work performed. We discovered that between the five years, 1968 through 1973, we had a 35% in crease in total line acres added to our system. This, of course, had the obvious effect of creating a substantial increase to our yearly maintenance budget. Instead of 14,000 acres of right of way, we now had approximately 22,000 acres to manage.
The need for a more sophisticated method of keeping records became evident when an attempt was made to document work accomplished on each line over a period of time. Furthermore, as the need arose to develop more detailed budget requests, it also became apparent that a more scientific approach for gathering inventory data on which to base our maintenance budgets was needed.
This resulted in the development of our existing program in which we utilize our IBM 370 computer.
The program is basically outlined in the flow chart shown on Fig. 1. The basic input data consist of field inventory data and summaries of work performed, such as clearing and/or chemical treatment, etc. From these data, we derive three basic summary print-outs (1) survey details and summary, (2) line summary, and (3) yearly summary. Once the basic information has been entered on to the computer tapes, a variety of other programs can also be adapted relative to amounts of various chemical used in a given year, cost comparisons by method of treatment, as well as many other programs.
The survey detail and summary print-out is derived from field data collected on our R/W vegetation inventory report form (Fig. 2) The field data are collected on this form on a structure-by-structure basis. Vegetation is recorded by species according to height classes, i.e., 0-3 feet, 3-6 feet, 6-9 feet, and over 9 feet. Vegetation is further classified as scattered, light, medium, or heavy density, and an estimate or percentage of a particular span requiring treatment, i.e., basal or foliage spraying and/or reclearing. Other pertinent information is also gathered, such as occurrence of farm land, Christmas tree plantations, highways, river or stream crossings and other pertinent environmental data, as well as occurrence of danger trees and R/W widening requirements. Measurements of R/W widths are also made at various points where changes are evident.
Distance between structures is obtained from engineering records maintained in the office. The appropriate data from the inventory report are then placed on standard IBM cards for transfer to magnetic tapes which are then added to the data base for the line and year summaries.
The structure-by-structure field inventory report has many uses. Besides its use as the basis for input for the detailed computer summary printout, it provides the contractor with information regarding the nature and quantities of work to be accomplished on a span-by-span basis. The field survey report also provides invaluable information pertaining to R/W conditions such as location of areas where vehicle crossings are impossible, environmentally sensitive areas and actual types of vegetation to be treated by structure location. It also shows the contractor the basis on which brush acres are computed.
The field inventory report is furthermore used as a tool in arriving at decisions relating to management techniques which are employed on a given right of way. The species composition, height classes and density, for example, play an important role in prescribing method of vegetation control, i.e., cutting or spraying, and the type of chemical to be used. Another very useful aspect of this report shows the location of danger trees and R/W widening requirements (Figure 3).
Although field data are presently accomplished by an on-the-ground inspection, we are investigating the feasibility of gathering this data by use of low altitude 35mm aerial photography through a cooperative research project with the University of Minnesota, College of Forestry. Preliminary results of this technique look favorable. Providing we can obtain adequate detail in species identification and height classification, we will no doubt change to this system of gathering our basic field data. A preliminary cost analysis for this type of aerial photography indicate average costs of $3.00 to $5.00 per line mile, which is approximately one half of our current costs for our on-the-ground inspections.
Line Summary (Fig. 4)
The individual line summary gives a computer print-out of all activity concerning a particular line. This information includes the line number, date of treatment, location by structure number, method and type of treatment, i.e., hand or mechanical clearing, ground foliage or basal spraying and/or aerial spraying, type of chemical used, number of acres treated, total cost and average cost per acre.
The primary value of this line summary lies in its use as a permanent reference which indicates type of treatment by year and the total number of acres treated as well as costs incurred. The summary of acres treated by respective years furthermore indicates progress or lack of progress which is being made with regards to “brush” acres treated. It furthermore shows the number of years a particular line has been under management and gives a relative measure of the effectiveness of various herbicides for controlling vegetative growth as indicated by number of brush acres.
The information from which the line summary is made is also the basis for our yearly summary report. This print-out summarizes work which has been accomplished on a year-by-year basis and indicates total number of acres treated along with total cost and cost per acre by treatment. This information becomes quite useful for budgeting purposes.
Another program which we plan to incorporate in our computer is a list of property owners by line number, legal description and structure number, where special considerations have been made for “no spraying,” etc.
We have found it convenient to file this data along with other information relating to the management of individual rights of way into a multiple divider classification folder. Each folder contains six separate divisions:
R/W summary
history, including line summary computer print-out
maps and drawings
correspondence and special conditions
work reports
field survey data and computer summary print-out
We also have a yearly folder in which we maintain our yearly computerized summaries, budget information, etc.
One might ask why such detailed record systems. It can be summed up in basic environmental and economic concerns. Right-of-way maintenance costs are inversely related to the stability of plant community development, i.e., the greater the stability of the plant cover types, the lower the long-term maintenance costs (Fig. 5). This is based on the principle that shrub communities are not readily invaded by trees once the original component of trees are removed, i.e., they become more stable. In order to attain maximum potential benefit of natural vegetative plant communities on right-of-way systems, it is vitally important to have adequate information pertaining to vegetative cover types so that management decisions can be made which are both economically feasible as well as ecologically sound. Furthermore, an adequate system of records pertaining to R/W vegetation management is likewise essential in order to efficiently achieve long-term management objectives.
Footnotes
↵1 Presented at 51st Annual Convention of International Shade Tree Conference in Detroit, Michigan in August 1975.
- © 1976, International Society of Arboriculture. All rights reserved.