Tree work words: utility and urban forestry
Right-of-way, readily climbable, line-clearance trimmer, MVCD, tree board and other words from utility vegetation rules and city tree programmes, each from the rule or programme page that uses it.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. Utility tree crews and city foresters work under written definitions. OSHA defines who a line-clearance tree trimmer is. Oregon defines which trees count as readily climbable. NERC fixes the clearance a transmission owner has to keep. This page lists what each named source says a word means, so that a term from a rule or a programme page can be matched to the page that defines it.
Each meaning is written in our own words from the page named under it. A word none of these pages defines is left out. The other word lists are on tree work words: saws and cutting and tree work words: law and permits, and the full list is the tree work glossary.
Utility vegetation words
| Term | Meaning and source |
|---|---|
| Right-of-way | Missouri's rule defines it as less than full ownership: a limited right for a public utility to use land owned by someone else to carry electricity, typically recorded as an easement. NERC's explanation says its meaning for transmission lines rests on engineering and construction considerations that fix the width of the corridor, and departs a little from the strict legal meaning. Source: Missouri Public Service Commission, 4 CSR 240-23; NERC, FAC-003-5 Transmission Vegetation Management |
| Vegetation | Oregon's rule and Missouri's rule use the same words: trees, shrubs and other woody plants. Source: Oregon Public Utility Commission rule, OAR 860-024-0016; Missouri Public Service Commission, 4 CSR 240-23 |
| Tree (Missouri) | A woody plant at least 12 feet tall at maturity with one main stem and, in most cases, a distinct head. Missouri defines a woody plant as a vascular plant with a perennial woody stem that supports growth above ground from year to year, and arboriculture as the cultivation of trees, shrubs and other woody plants. Source: Missouri Public Service Commission, 4 CSR 240-23 |
| Vegetation management | Missouri defines it as removing vegetation or preventing its growth to keep conditions safe around energized conductors and keep electric service reliable, using biological, chemical, cultural, manual and mechanical methods, and giving the utility access to the conductor. Maryland's rule lists what a utility program must address: pruning and removal, work around poles and substations, manual, mechanical or chemical work along rights-of-way, inspection afterwards, cultural control, public education, notice and debris. Source: Missouri Public Service Commission, 4 CSR 240-23; Maryland Public Service Commission, COMAR 20.50.12.09 |
| Integrated vegetation management (IVM) | Hydro One says its approach follows best practices including integrated vegetation management, balancing customer input, reliability data and environmental concerns. The page lists tree trimming or cutting, brush control, selective herbicide application and pollinator-friendly habitat where feasible among its work. It does not give a formal definition, and neither does Missouri's list of methods. Source: Hydro One, vegetation management page; Missouri Public Service Commission, 4 CSR 240-23 |
| Cyclical vegetation management, trim cycle | Maryland's rule sets a schedule for utilities. For a 4-year trim cycle it names shares of total distribution miles to be done within 12, 24 and 36 months and by the end of the 4 years, and requires notice to owners or occupants before planned cyclical work. Source: Maryland Public Service Commission, COMAR 20.50.12.09 |
| Readily climbable | Oregon defines vegetation with low limbs reachable from the ground and close enough together to be climbed by a child or average person without a ladder or special equipment, and with a main stem or branch that would support a person within arms' reach of an uninsulated energized line, or close enough to be hurt by direct or indirect contact. The rule asks operators to trim or remove it to minimise access to a high voltage conductor by the public. Source: Oregon Public Utility Commission rule, OAR 860-024-0016 |
| Volts | Oregon and Missouri both define volts in their vegetation rules as nominal voltage levels, measured phase to phase. Source: Oregon Public Utility Commission rule, OAR 860-024-0016; Missouri Public Service Commission, 4 CSR 240-23 |
| Energized, energized conductor | OSHA defines energized as electrically connected to a source of potential difference, or electrically charged so as to have a potential significantly different from that of earth nearby. Missouri defines an energized conductor as a circuit or equipment through which electricity is flowing or usually flows. Source: OSHA, 29 CFR 1910.269 definitions; Missouri Public Service Commission, 4 CSR 240-23 |
| Distribution line, transmission line | Missouri separates them at 200,000 volts. A distribution line is a primary line energized at less than 200,000 volts. A transmission line carries electricity from a generating plant to distribution lines and is operated at or above 200,000 volts. Oregon's rule has separate clearances for conductors above 200,000 volts. Source: Missouri Public Service Commission, 4 CSR 240-23; Oregon Public Utility Commission rule, OAR 860-024-0016 |
| Rural, urban | Missouri counts customers per circuit mile: fewer than 35 is rural and 35 or more is urban. Source: Missouri Public Service Commission, 4 CSR 240-23 |
| Line-clearance tree trimming | OSHA defines it as pruning, trimming, repairing, maintaining, removing or clearing trees, or cutting brush, within 10 feet (3.05 meters) of electric supply lines and equipment at 50 kilovolts to ground or less, with 4 inches more for every 10 kilovolts above 50. A note says the section covers only this work when done to clear space around power lines on behalf of the organisation that operates them, and that trimming for a homeowner or other entity is outside it. Source: OSHA, 29 CFR 1910.269 definitions |
| Line-clearance tree trimmer | OSHA defines it as an employee who, through related training or on-the-job experience or both, is familiar with the special techniques and hazards of line-clearance tree trimming. A note says a trimmer is not a qualified employee under section 1910.269 without the training the section requires, but under OSHA's electrical safety work practices standard in subpart S a line-clearance tree trimmer is considered a qualified employee. Source: OSHA, 29 CFR 1910.269 definitions |
| Qualified employee (qualified person) | OSHA defines it as an employee knowledgeable in the construction and operation of the electric power generation, transmission and distribution equipment involved, along with the hazards. The definition's notes say the training in paragraph (a)(2)(ii) is needed, and that a trainee under direct supervision of a qualified person counts as qualified for the duties at their level of training. Source: OSHA, 29 CFR 1910.269 definitions |
| Minimum Vegetation Clearance Distance (MVCD) | NERC's explanation says it is a calculated minimum distance derived from the Gallet equation, a flash-over method used in designing high voltage transmission lines, and that keeping vegetation that far from conductors prevents flash-over to the vegetation. Table 2 of the standard gives values by voltage and altitude. Source: NERC, FAC-003-5 Transmission Vegetation Management |
| Encroachment, fall-in, blowing together | FAC-003-5 requirement 1 lists the encroachments it addresses: into the MVCD seen in real time, from a fall-in from inside the right-of-way that caused a vegetation-related sustained outage, from vegetation and lines blowing together inside the right-of-way that caused such an outage, and from vegetation growth into the MVCD that caused one. Source: NERC, FAC-003-5 Transmission Vegetation Management |
| Vegetation inspection | In FAC-003-5 requirement 6 an owner inspects 100% of its applicable transmission lines at least once per calendar year, with no more than 18 calendar months between inspections of the same right-of-way. NERC's supplement says its glossary definition was changed to let maintenance and vegetation inspections be done at the same time. Source: NERC, FAC-003-5 Transmission Vegetation Management |
City tree programme words
| Term | Meaning and source |
|---|---|
| Tree board, tree department | Tree City USA's first standard is a community tree board, department or position with legal authority and responsibility for public tree care decisions. The page lists a city or volunteer tree board, a forestry, parks, public works or planning department, or a city manager as entities that could qualify. Source: Arbor Day Foundation, Tree City USA standards |
| Public tree care ordinance | Tree City USA's second standard is a community-wide law, ordinance or legally enforceable policy that says who is responsible for urban and community forestry, directs the establishment, conservation, protection or maintenance of trees, and addresses public trees. Incorporated communities with an ordinance structure submit an ordinance, not a policy. Source: Arbor Day Foundation, Tree City USA standards |
| Tree and forest assessment, inventory, canopy study | Tree Cities of the World's third standard says a city must show it understands its tree and forest resource through an assessment, inventory or canopy study. Source: Tree Cities of the World, how it works |
| Tree Equity Score | American Forests describes it as an equity-first standard to guide investment in urban tree infrastructure, starting with neighborhoods of greatest need. The page's headline figure is 200K scores for urban neighborhoods in the United States. Source: American Forests, Tree Equity Score about page |
Reading these sources
OSHA's definitions are federal and apply to the work 1910.269 covers. Oregon, Missouri and Maryland are three state rules, each from its public service or utility commission, so their meanings stop at the state line. The Missouri rule copy read carries the printed date June 30, 2008. NERC's FAC-003-5 is a reliability standard for transmission owners, and the explanations quoted are from its supplemental material. Hydro One is an Ontario utility and its page describes its practice, not a rule.
The programme words come from the Arbor Day Foundation, Tree Cities of the World and American Forests, which are recognition programmes and a data project, not regulators. What the rules require of utilities is on utility vegetation management rules, and the line-clearance training and rules are on utility line clearance.
Sources
- OSHA via eCFR, 29 CFR 1910.269 electric power generation, transmission and distribution, definitions, read October 9, 2026
- Oregon Public Utility Commission, OAR 860-024-0016 Minimum Vegetation Clearance Requirements, as published at oregon.public.law, read October 9, 2026
- NERC, FAC-003-5 Transmission Vegetation Management, read October 9, 2026
- Missouri Public Service Commission, 4 CSR 240-23 Electric Utility Operational Standards, printed June 30, 2008, read October 9, 2026
- Maryland Public Service Commission, COMAR 20.50.12.09 Vegetation Management Requirements, read October 9, 2026
- Hydro One, Vegetation management page, read October 9, 2026
- Arbor Day Foundation, Tree City USA standards, read October 9, 2026
- Tree Cities of the World, How it works, read October 9, 2026
- American Forests, Tree Equity Score about page, read October 9, 2026