UTILITY VEGETATION MANAGEMENT AND BULK ELECTRIC RELIABILITY 

REPORT FROM THE FEDERAL ENERGY REGULATORY COMMISSION 

SEPTEMBER 7, 2004
Executive Summary 

Electric transmission owners and operators conduct vegetation management to 

prevent physical contact between transmission lines and nearby vegetation that could 

cause a transmission line to fail. On August 14, 2003, an electric power blackout affected 

large portions of the Northeast and Midwest United States and Ontario, Canada. 

President George W. Bush and Prime Minister Jean Chrétien established a joint U.S.-

Canada Power System Outage Task Force (Task Force) to investigate the causes of the 

blackout and how to reduce the possibility of future outages. On April 5, 2004, the Task 

Force issued a Final Blackout Report1

 stating that one of the four primary causes of the 

blackout was inadequate vegetation management (tree pruning and removal). 

In response to the Final Blackout Report, the Federal Energy Regulatory 

Commission (Commission) directed all designated transmission owners to file reports 

with the Commission by June 17, 2004, explaining their vegetation management 

practices for designated transmission facilities and rights-of-way.2

 The Commission staff 

worked with the leadership of the National Association of Regulatory Utility 

Commissioners’ (NARUC) ad-hoc Committee on Critical Infrastructure to analyze these 

reports to look for significant patterns and potential problems in the vegetation 

management practices of the electric industry. This report to Congress summarizes the 

Commission’s findings and recommendations. In this report, the Commission also 

recommends that Congress enact legislation providing for mandatory, enforceable 

reliability rules. 

Key Observations 

 The transmission owners were asked to report on the results of their most recent 

transmission line vegetation management inspections, necessary remedial actions 

identified, and whether such actions had been completed before the summer 2004 peak 

 1

 U.S.-Canada Power System Outage Task Force, Final Report on the August 14th

Blackout in the United States and Canada: Causes and Recommendations (April 2004) 

(Final Blackout Report). 

2

 Order Requiring Reporting on Vegetation Management Practices Related to 

Designated Transmission Facilities, 107 FERC ¶ 61,053 (2004) (Vegetation Management 

Order). “Designated transmission facilities” are defined, for the purposes of the 

Vegetation Management Order only, as transmission lines with a rating of 230 kV or 

higher as well as tie-line interconnection facilities between control areas or balancing 

authority areas (regardless of kV rating) and “critical” lines as designated by the regional 

reliability council. See NERC, August 14, 2003 Blackout: NERC Actions to Prevent and 

Mitigate the Impacts of Future Cascading Blackouts at 9 n.3 (Feb. 10, 2004). 
2 

load season. Review of the vegetation management filings found that it appears 

transmission owners and operators have performed extensive vegetation management 

along the nation’s high-voltage transmission network, which should produce better grid 

reliability during the summer. However, there is a wide range of vegetation management 

practices and procedures among the reporting transmission owners. There is very little 

uniformity in regard to right-of-way width,3

 vertical line clearance,4 inspection 

frequency,5

 and vegetation management guidelines6 used. The lack of uniformity may be 

understandable in part, as transmission owners must design their vegetation management 

practices based on factors such as the demands of the terrain, location, climate, vegetation 

species, and local laws and regulations. 

 The Commission recognizes that, while the data filed in response to the 

Vegetation Management Order reveals each transmission owner’s practice, it does not 

directly address how effective the practice has been in limiting preventable transmission 

line outages. The Commission did not ask for such data in the April request, because 

similar data are now being reported to the Western Electricity Coordinating Council and 

to the North American Electric Reliability Council (NERC). Such a review is beyond the 

scope of this report. 

 Transmission owners report that they are not able to acquire all necessary permits 

to maintain their rights-of-way from various federal and state agencies. However, this 

problem could be alleviated, at least in part, if the acquisition of these permits is made a 

higher priority on the part of transmission owners. For instance, transmission owners 

could allow additional lead time to acquire many needed permits. The agencies 

responsible for issuing permits, however, should ensure that they have clear rules and 

procedures for issuing permits in a timely manner. 

 With respect to any jurisdiction issues that may arise involving vegetation 

management, it is important that state and federal regulators continue to coordinate so 

that jurisdictional considerations do not impede effective vegetation management. 

 3 A right-of-way is a segment of land used for the route of a transmission line. A 

right-of-way should be devoid of vegetation that can interfere with a transmission line. 

The right-of-way width is the distance between the outer bounds of a right-of-way. 

4 The vertical distance between a tree or vegetation and an electric transmission 

wire. 

5

 The time between complete inspections of a utility’s transmission system, e.g., 

semiannual, annual, etc. 

6

 The guidelines that utilities report they adhere to in regards to the management of 

vegetation along transmission lines. 
3 

 The Commission believes that better coordination among federal agencies and 

between the federal and state governments to develop clear, consistent policies and 

procedures for timely and effective vegetation management by transmission owners could 

help to alleviate many real and perceived obstacles to proper vegetation management. 

The transmission owners reported that vegetation management approvals on 

federally managed rights-of-way are particularly problematic in the Western United 

States. The Council on Environmental Quality (CEQ) coordinates federal environmental 

efforts and helps resolve inter-agency differences over environmental issues. The 

Commission believes federal agencies and the CEQ should work together on vegetation 

management on federal rights-of-way. In addition, the CEQ could facilitate coordination 

with Native American tribes for vegetation management on Native American tribal 

lands. We understand that vegetation management practices affect the environment and 

look forward to working with other agencies to coordinate efforts to assure that neither 

the environmental quality of federal lands nor regional electric reliability are put at risk. 

Summary of Recommendations 

1) The United States Congress should enact legislation to make reliability standards 

mandatory and enforceable under federal oversight. 

2) Effective transmission vegetation management requires clear, unambiguous, 

enforceable standards that adequately describe actions necessary by each responsible 

party. 

3) With respect to any jurisdiction issues that may arise involving vegetation 

management, it is important that state and federal regulators continue to coordinate so 

that jurisdictional considerations do not impede effective vegetation management. 

4) Federal and state regulators should allow reasonable recovery for the costs of 

vegetation management expenses. 

5) While permitting and environmental requirements properly protect public lands, 

the procedures implementing those protections may be inconsistent and time-consuming 

and have the potential to significantly hinder transmission vegetation management. The 

Commission should work with the CEQ and land management agencies to better 

coordinate these requirements. 

6) Federal, state and local land managers should develop “rush” procedures and 

emergency exemptions to allow utilities to correct “danger” trees7

 that threaten 

transmission lines, from both on and off documented rights-of-way. 

 7

 A danger tree is a tree that is dead or dying and has the potential to fall into a 
4 

7) Five-year vegetation management cycles should be shortened, and the 

Commission and states should look at the cost-effectiveness of more aggressive 

vegetation management practices. 

8) Transmission owners should fully exercise their easement rights for vegetation 

management and better anticipate and manage the permitting process for scheduled 

vegetation management. 

9) Variances in vegetation management practices may be resolved in the NERC 

vegetation management standard development process; if they are not, the Commission 

may seek to convene the industry, states and other stakeholders to address the remaining 

issues. 

10) State regulators and the utility industry should work through NARUC, the 

National Conference of State Legislators, and other organizations to help state and local 

officials better understand and address transmission vegetation management. 

Introduction 

On August 14, 2003, an electric power blackout occurred over large portions of 

the Northeast and Midwest United States and Ontario, Canada. The blackout lasted up to 

two days in some areas of the United States and longer in some areas of Canada. It 

affected an area with over 50 million people and 61,800 megawatts of electric load. In 

the wake of the blackout, a joint U.S.-Canada Task Force (Task Force) undertook a study 

of the causes of that blackout and possible solutions to avoid future such blackouts. The 

Task Force’s Final Report was issued on April 5, 2004. 

The Task Force identified FirstEnergy Corporation’s (FirstEnergy) failure to 

adequately prune trees and manage vegetation in its transmission rights-of-way as one of 

the four primary causes of the August 14, 2003 blackout.8

 The blackout investigation 

explained that, during the hour before the cascading blackout occurred, three FirstEnergy 

345 kV transmission lines failed as a result of contact between the lines and overgrown 

vegetation that encroached into the required clearance zone for the lines.9

 It stated that 

“because the trees were so tall . . . each of these [three] lines faulted under system 

conditions well within specified operating parameters.”10 

 

right-of-way close to a line. 

8

 Final Blackout Report at 20. 

9 Id. at 57-67. 

10 Id. at 58. 
5 

The Final Blackout Report also compared the August 2003 blackout with seven 

previous major outages and concluded that conductor contact with trees was a common 

factor among the outages.11 The Task Force emphasized that vegetation management is 

critical, and that many outages can be prevented by managing vegetation before it 

becomes a problem.12 It also noted that investigation reports from previous major 

outages recommended paying special attention to the condition of vegetation on rightsof-way and the need for preventative maintenance in this area. 

In March 2004, the Commission made available to the public a 128-page 

vegetation management report, prepared to support the blackout investigation.13 The 

report details problems with vegetation management relating to the August 2003 

blackout, and the impact of vegetation management on electric reliability. The report 

concludes that the August 2003 blackout likely would not have occurred had the rightsof-way been maintained for three 345 kV transmission lines that tripped due to tree-line 

contacts.14 It also concludes that utilities responsible for the right-of-way maintenance 

had in place vegetation management programs that were in line with current industry 

norms. Further, it concludes that current industry “standards” are inadequate and must be 

improved. The CNUC Final Vegetation Report recommends specific practices that 

would reduce the likelihood of tree and power line contacts and provides 

recommendations for the oversight and enforcement of utility vegetation management 

activities. 

On April 19, 2004, the Commission issued the Vegetation Management Order 

requiring all entities that own, control or operate designated electric transmission 

facilities in the lower 48 states to provide information on their vegetation management 

practices. This order was issued pursuant to section 311 of the Federal Power Act, 16 

U.S.C. § 825j (2000) which authorizes the Commission to conduct investigations in order 

to secure information necessary or appropriate as a basis for recommending legislation. 

The Commission ordered that designated transmission owners describe in detail 

the practices and standards that the transmission owner uses for control of vegetation near 

designated transmission facilities, and indicate the source of any standard utilized (e.g. 

state law or regulation, historical practice). In addition, transmission owners were asked 

 11 Id. at 107. 

12 Id. at 59. 

13 CN Utility Consulting, Utility Vegetation Management Final Report, (March 

2004) (CNUC Final Vegetation Report). The CNUC Final Vegetation Report is available 

on the Internet at www.ferc.gov/cust-protect/moi/blackout.asp. 

14 Id. at 26-27. 
6 

to describe the clearance assumptions or definition used for the appropriate distance 

between vegetation and the facilities, how often the transmission provider inspects that 

facility for vegetation management purposes, whether identified remediation has been 

completed as of June 14, 2004, and any factors that the respondent believes prevents, or 

unduly delays, the performance of adequate vegetation management.15 

This report analyzes the information gathered pursuant to the Vegetation 

Management Order, provides relevant additional information regarding the current status 

of vegetation management practices, and offers a recommendation for Congressional 

consideration. 

Review and Analysis Method 

 The Commission received 161 responses from transmission owners.16 On June 

21-22, 2004, Commission staff, along with three state commissioners, Connie Hughes of 

New Jersey, Don Mason of Ohio, and Judith Ripley of Indiana, representing the 

leadership of the NARUC ad-hoc Committee on Critical Infrastructure, performed an 

initial review of the vegetation management responses.17 This initial two-day review was 

intended to identify any immediate issues that could potentially impact electric grid 

reliability requiring rapid follow up by state or federal regulators. In addition, it looked 

for progress made since the blackout of the previous year, fact patterns suggesting 

additional inquiry is required, and a general overview of current vegetation management 

practices. The initial review was followed up by a more intensive Commission staff data 

analysis. This analysis included the creation of a database that tracked: 

• all respondents’ right-of-way width maintained in feet by voltage, 

• vertical line clearance in feet by voltage, 

• ground and aerial inspection frequency, 

• vegetation management cycle,18 and 

• vegetation management guidelines utilized, if any. 

 15 Vegetation Management Order at P 12. 

16 Some respondents provided responses on behalf of multiple operating 

companies or multiple transmission owners. 

17 Edison Electric Institute (EEI) prepared templates for its members to use in 

filing the requested data. Many EEI members used these templates. The templates made 

it easier for Commission staff to review the filings. 

18 The period of time required for a utility to perform maintenance including the 

pruning of all vegetation and the removal of all vegetation of concern on its entire 

transmission system. 
7 

 Commission staff reviewed the data in the five categories above and looked for 

patterns in vegetation management practices.19

Findings 

 The majority of respondents have completed necessary vegetation management 

remediation measures identified during the most recent inspection of their transmission 

lines. While this does not guarantee that there will not be adverse impact to grid 

reliability caused by vegetation interfering with transmission lines, it is a positive 

indication of reduced risk to reliability. However, 29 percent of respondents identified 

some line vegetation management remediation that was not completed by the June 17 

filing date and may not be performed this summer.20 A list of these respondents is 

provided in Attachment A. The results suggest that a significant amount of the 

remediation occurred between April 19, 2004 and June 14, 2004. 

Utility vegetation management practices vary significantly. While some variation 

is expected because vegetation management practices are affected by climate, terrain, 

vegetation species, local laws, and regulations, other variations are unexplained. Below 

is a discussion of reported data on right-of-way width, vertical clearances, inspection 

frequency, vegetation management cycles, and vegetation management guidelines 

followed. Some of these variations may be resolved in the NERC vegetation 

management standard development process;21 if they are not, the Commission may seek 

to convene the industry, states and other stakeholders to address the remaining issues. 

1. Right-of-way Width 

 

19 In their filings, certain respondents asked for and were granted protection 

regarding specific transmission line information under the Commission’s Critical Energy 

Infrastructure Information (CEII) policy. CEII is information concerning proposed or 

existing critical infrastructure (physical or virtual) that relates to the production, 

generation, transmission or distribution of energy. While this report does not disclose 

any specific CEII data, the Commission’s conclusions reflect its review of such data. 

20 In some instances, the transmission owner/operator reported that remediation 

before the summer was not needed and would be completed as part of the regular 

vegetation management cycles later in the year. In other instances, the respondent states 

that there is no immediate threat to the line. Some stated that the work would be 

completed shortly after June 17 or as soon as possible. In at least one case, the required 

work was pending reaching agreement with a landowner. 

21 NERC recently initiated a vegetation management standard development 

process. See ftp://www.nerc.com/pub/sys/all_updl/docs/bot/Agenda-Items0604/Item12e.pdf. 
8 

 Right-of-way widths vary significantly among the reporting transmission owners. 

Generally, right-of-way width increases as line voltage increases. Higher voltage lines 

require wider rights-of-way because greater separation is needed between conductors. 

Wider right-of-way widths are also necessary to accommodate multiple lines and in some 

cases more than one tower. Since right-of-way width depends on many factors, and since 

some respondents provided ranges that depend on such factors as the number of circuits 

on a right-of-way, no pattern was identified from the data on the range of right-of-way 

widths. Table 1 shows the range of responses by voltage class. 

Table 1. Right-of-Way Width 

Right-of-Way Width 

500 kV 345 kV 230 kV Less than 230 kV 

Minimum Width 

(ft) 

# of 

Companies 

Minimum 

Width (ft) 

# of 

Companies 

Minimum Width 

(ft) 

# of 

Companies 

Minimum 

Width (ft) 

# of 

Companies 

Less than 125 4 Less than 75 6 Less than 75 40 Less than 50 51 

126-175 21 76-125 36 76-125 36 51-125 41 

176 > 13 126 > 30 126 > 30 126 > 7 

In general, if a utility has a wider right-of-way, well documented right-of-way 

easement rights, and exercises those rights fully, it will be more successful in avoiding 

vegetation-line contact than a utility that maintains narrower rights-of-way. A narrow 

right-of-way increases the risk of contact with vegetation that is outside of the right-ofway and adjacent to the transmission line. Expert commentary included in the CNUC 

Final Vegetation Report stated, “[m]ost tree/power line contacts occur when trees fall 

onto lines from outside the rights-of-ways or corridors. Many utilities are slow to act to 

address this issue due to the perception of increased costs and the pressure from 

landowners etc. to leave trees standing.”22 

2. Inspection Frequency 

Vegetation management inspections are performed to inspect the status of 

vegetation and the rights-of-way surrounding electric transmission facilities. During 

these inspections, vegetation of concern is noted and scheduled for remediation. 

Typically, a utility will utilize a combination of aerial and ground inspections. Ground 

inspections are performed by walking or driving the length of transmission lines to 

inspect the condition of vegetation. While slow, ground inspections may be more 

effective because they enable an inspector to more thoroughly view vegetation conditions 

and the relationship between vegetation and the wire. Aerial inspections are performed 

using aircraft (a helicopter or a small plane flying at low altitude) to visually inspect the 

 22 CNUC Final Vegetation Report at 115. 
9 

condition of vegetation. Given the greater distance from the vegetation and the speed of 

aerial inspection, it is considered to be less reliable and thorough than ground inspection. 

Annual, semi-annual, or more frequent aerial patrols are part of the transmission 

inspection practice of 105 utilities, twenty-five of which conduct aerial inspections more 

frequently than twice a year. Table 2 summarizes the responses. 

Table 2. Aerial Inspection Frequency 

Aerial Inspection 

Frequency # of 

Companies

More than twice 

a year 

25 

Semi-annual 34 

Annual 46 

Biennial 6 

Every 3 years 1 

> than 3 Years 3 

As Needed 8 

Did Not Report 38 

 Most transmission owners use aerial patrols to identify areas that need remediation 

or areas that will need remediation soon. Aerial inspections are followed by additional 

ground inspection or remediation. 

Over 100 respondents indicate that they conduct annual or more frequent ground 

inspections of their entire system. Ground patrols are more effective in identifying 

vegetation-related problems.23 Table 3 summarizes the responses. 

 23 CNUC Final Vegetation Report at 49. 
10 

Table 3. Ground Inspection Frequency 

Ground Inspection 

Frequency # of 

Companies

More than twice 

a year 

7 

Semi-annual 22 

Annual 76 

Biennial 6 

Every 3 years 6 

> than 3 Years 25 

As Needed 12 

Did Not Report 7 

 As with right-of-way width, patrol frequency and method varies significantly 

among reporting utilities. This could be due to the variation in the number of 

transmission circuit miles owned or operated by the utility, terrain, and vegetation 

characteristics. 

3. Vertical Clearance 

 Vertical clearance is the distance between a wire and the vegetation directly below 

it.24 The minimum vertical clearance requirement increases by line voltage (although 

some transmission owners reported the same vertical clearance for all voltage classes). 

The maintenance of sufficient vertical distance between the conductor and vegetation is 

essential because direct physical contact is not necessary for a line outage to occur. An 

electric arc can occur between a part of a tree and a nearby high-voltage conductor 

without sufficient clearance.25 These electric arcs can cause fires and line outages. 

Vegetation management practices should maintain a minimum vertical clearance between 

a line and a tree. The pruning should create clearances with a healthy safety margin 

beyond the minimum required clearance that will last until the next scheduled pruning or 

treatment. Table 4 shows vertical clearances used by reporting utilities. 

 24 Vegetation can interfere with power lines from below, sides, and above and 

appropriate clearance must be maintained all around the wire. This section discusses 

vertical line clearance as an example of the variation among utilities in maintaining line 

clearances. 

25 In effect, electricity on a transmission wire can “jump” a very short distance 

from the wire to tree limbs without direct contact, creating a short circuit that can lead to 

a line outage. 
11 

Table 4. Vertical Clearances Reported 

Vertical Clearance Table 

500 kV 345 kV 230 kV Less than 230 kV 

Clearance 

(ft) 

# of 

Companies 

Clearance 

(ft) 

# of 

Companies 

Clearance 

(ft) 

# of 

Companies 

Clearance 

(ft) 

# of 

Companies 

0-15 11 0-15 17 0-10 23 0-10 16 

16-20 11 16-20 17 11-15 17 11-15 20 

21-25 9 21-25 12 16-20 24 16-20 14 

26> 8 26 > 14 21-25 16 21-25 3 

26 > 13 26 > 5 

 There is no apparent rationale for the wide variance in vertical clearance 

requirements.26 The current industry effort through NERC to develop a vegetation 

management standard should resolve this issue. 

4. Vegetation Management Cycle 

 A vegetation management cycle is loosely defined as the time it takes to complete 

the pruning and removal of trees or other vegetation on a utility’s entire transmission 

system. In most cases, a utility prunes or treats a portion of its total circuit-miles of rightof-way in each year; once the circuit is completed, the company starts the cycle over. 

The Vegetation Management Order did not formally request this information, but the 

CNUC Final Vegetation Report found that a five-year cycle is the industry norm. 

Furthermore, the report found that the five-year cycle is insufficient to maintain 

reliability. 

 Of the 70 respondents that volunteered their vegetation management cycles, many 

indicate that they prune and remove vegetation along their lines within a five-year or 

longer interval.27 Table 5 summarizes the responses. 

 26 There could have been varying interpretations of the reporting requirement (e.g., 

clearance achieved at the time of pruning vs. minimum clearance maintained). However, 

the EEI templates used by a large number of respondents instructed that “minimum 

clearance maintained between conductor and vegetation” be reported. 

27 A five-year cycle is consistent with the industry practice; however, common or 

average industry practices need improvement. Final Blackout Report at 59. 
12 

Table 5. Pruning Cycle 

Pruning Cycle 

Frequency 

# of 

Companies 

0-2 years 11 

3-4 years 35 

5 or More 

years 24 

 In the future, the Commission and the industry should work to identify the 

correlation between vegetation management practices and actual vegetation-caused 

transmission line outages. 

When managing vegetation, 93 companies employ herbicides to limit vegetation 

growth; others use mechanical techniques to cut vegetation on rights-of-way; and some 

use a combination of both.28 

5. Current Vegetation Management Guidelines 

Establishing clear, unambiguous standards pertaining to maintenance of safe 

clearances of transmission lines from obstructions in rights-of-way was one of the 

recommendations of the Final Blackout Report.29 The vast majority of transmission 

owners report that they follow the National Electrical Safety Code (NESC) rules or 

American National Standards Institute (ANSI) guidelines, or both when managing 

vegetation around transmission lines. The NESC deals with electric safety rules, 

including transmission wire clearance standards, while the applicable ANSI code deals 

with the practice of pruning and removal of vegetation. However, these rules and 

guidelines are not specific with regard to clearances between transmission lines and 

vegetation and are subject to interpretation. Nor do these rules provide a performance 

target for keeping vegetation from conflicting with transmission lines. Furthermore, 

these standards are not enforceable upon transmission owners, but have been adopted by 

NESC and ANSI as guidelines for appropriate practice. 

• 104 utilities indicate that they adhere to NESC standards for transmission 

system maintenance. 

• 92 of these specifically adhere to NESC Rule 218, which only provides that 

 28 Mechanical and chemical techniques are not mutually exclusive in general. 

Rather, mechanically clearing, e.g. with a bushhog, might take place followed by 

treatment with herbicide to retard regrowth. 

29 Final Blackout Report at 154. 
13 

trees that may interfere with conductors should be trimmed or removed. NESC 

Rule 218 does not prescribe clearances. 

• 12 reported that they specifically follow NESC Rule 232, 233 or 234 which 

prescribes clearances of wires from ground, structures, and other installations. 

• 34 respondents follow ANSI A300, which deals with proper tree pruning 

techniques to maintain the health of the tree, and does not contain any 

clearance requirements. 

• ANSI Z133, used by 22 transmission owners, provides guidelines for utilities 

related to worker and public safety during tree pruning and removal operations. 

• A large number of respondents adhere to NESC standards in conjunction with 

ANSI standards such as A300. 

• 96 transmission owners report that they use internally-developed, state, or 

other guidelines. 

 Respondents did not explain why they follow a particular standard. As stated 

earlier, NERC is in the process of developing a vegetation management standard that may 

resolve the current lack of a clear, unambiguous standard. 

Good Practices 

 The CNUC Final Vegetation Report identified a number of good utility vegetation 

management practices. Among these good practices for existing rights-of-way are: 

• Application of wire zone – border zone concepts (described below) 

• Proper consideration of line sag and sway 

• Frequent field inspection of vegetation conditions 

• Comprehensive public education programs 

In reviewing the filings, Commission identified a number of utilities that report 

practices consistent with the best practices identified in the CNUC Final Vegetation 

Report. Some examples follow. 

One good practice relates to customer education. For example, some utilities have 

public outreach programs that educate the public about tree types and line clearances so 

that citizens will have the knowledge to report vegetation that is dangerous to 

transmission wires. 

Several transmission owners employ a wire zone – border zone approach which is 

both environmentally friendly and effective in ensuring reliability. This method involves 

creating a low-growing vegetation environment directly under transmission lines, which 

physically prevents dangerous vegetation from encroaching into energized transmission 

facilities. The CNUC Final Vegetation Report stated that the wire zone-border zone has 
14 

“been proven to be effective in reducing and/or eliminating outages related to vegetation 

on transmission ROW [rights of way].”30 The wire zone-border zone concept is depicted 

in the graphic below. 

Several companies have taken measures to improve vegetation managementrelated reliability. Certain utilities, for example, conduct frequent ground and aerial 

patrols, as well as an inspection of all of its power lines after every major storm. 

Reported Obstacles to Effective Vegetation Management 

In trying to understand the state of the industry’s vegetation management 

programs, the Vegetation Management Order sought information on factors that the 

utilities believe prevent or unduly delay their performance of adequate vegetation 

management. Sixty-six utilities report that their efforts to properly maintain their 

transmission lines are impeded by a variety of federal and state regulations that legally or 

practically prevent them from performing effective vegetation management. While such 

ordinances can be problematic and hinder the vegetation management process, proper 

planning and foresight on the part of the utilities, including allowances for additional lead 

time, would likely reduce the threat to vegetation management caused by some 

ordinances. 

 30 CNUC Final Vegetation Report at 21. 
15 

List of Reported Obstacles 

Reported Obstacles Responses

U.S. Forest Service 22 

U.S. Fish and Wildlife 

Service 

12 

National Park Service 6 

Departments of 

Transportation 

6 

Other 

Federal/State/Local 

Governments 

35 

Private Landowners 20 

Other 10 

No transmission owners complained of the financial costs of vegetation 

management. 

In many instances, a situation may arise in which a transmission owner is not able 

to plan for vegetation management. For example, trees can become hazardous to a line 

suddenly, as when a tree is dead or dying and has the potential to fall into a right-of-way 

and impact a line. These are a risk to reliability as long as the situation is not corrected, 

and so must be dealt with on a priority basis. Many transmission owners reported that the 

permitting processes can impede action necessary to properly manage situations such as 

this. 

The conflicting goals and requirements for environmental protection and electric 

reliability create practical problems for vegetation management. Transmission owners 

cite federal regulations and their enforcement programs most frequently as impeding their 

ability to properly manage the vegetation within transmission line rights-of-way. 31 

Twenty-two transmission owners cited U.S. Forest Service (Forest Service) restrictions 

on transmission owners across the country. They state that the Forest Service requires 

impact studies on wildlife and habitat impacts, requires environmental impact 

assessments, and limits the use of access roads to transmission rights-of-way and has 

inconsistent permitting procedures across the National Forests. In addition, twelve 

utilities claim that the U.S. Fish and Wildlife Service restricts the times at which trees can 

be pruned and limits herbicide use in order to maintain endangered species habitats. If 

 31 Some of the land management agencies have already begun streamlining their 

permitting processes. For example, the Forest Service began overhauling its permitting 

and environmental review process over a year ago. These changes should reduce the 

impact of permitting on vegetation management. 
16 

herbicide use is limited, many manually or mechanically removed trees can re-sprout and 

quickly grow back into power lines. Utilities also report that the various state 

Departments of Transportation had restricted tree pruning and removal in the name of 

“beautification” efforts. Otter Tail Power reports that the U.S. Department of 

Transportation, the U.S. Fish and Wildlife Service, and the Department of Natural 

Resources have repeatedly planted trees in its rights-of-way. 

 

Several companies stated that state government organizations had taken action that 

they believed hindered their reliability programs as well. For instance, PacifiCorp reports 

that the Utah Department of Transportation had planted trees directly under several of its 

345 kV transmission lines and would not allow them to be pruned. The New York State 

Department of Environmental Conservation requires transmission owners to file 

“Temporary Revocable Permits” that take up to two years to process for transmission 

owners to get access to trees that need to be managed. 

Respondents also claim that a variety of local regulations and property owners 

prevent effective vegetation management. One of the most frequent claims is local and 

private entities limit the use of herbicides and the removal of trees. Some local park 

restrictions hinder trucks from accessing power lines. Native American tribes are 

sovereign and can restrict transmission owners in numerous ways when transmission 

rights-of-way pass through tribal land. For many utilities, attempting to manage 

numerous local and private restrictions can be extremely burdensome and can result in 

failure to conduct effective vegetation management. For example, the outage that 

occurred on Cinergy’s 345 kV Columbus – Bedford line on August 14, 2003 was due to a 

property owner’s refusal to allow Cinergy to complete the required work.32 Cinergy had 

documented rights at the location but work was halted due to a court-granted temporary 

injunction obtained by the property owner. 

Need For Legislation 

 Ineffective vegetation management was a major cause of the August 14, 2003 

blackout and a contributing factor to other large-scale blackouts. The U.S.-Canada Task 

Force found that clear, unambiguous, and enforceable standards are needed to reduce the 

potential for reoccurrence of vegetation related transmission line outages and 

recommended that NERC, in cooperation with the industry and the appropriate 

governmental agencies, develop such a standard.33 The Commission’s review of the 

responses submitted confirms a lack of common standards and significant variations 

among utilities in their vegetation management practices. 

 32 CNUC Final Vegetation Report at 36. 

33 Final Blackout Report at 154. 
17 

NERC recently initiated a vegetation management standard development process. 

The Commission supports NERC’s initiative to develop a clear, unambiguous vegetation 

management standard. However, adherence to NERC standards will be voluntary unless 

Congress enacts legislation with a clear federal framework for mandating development 

and enforcement of this and other reliability rules. 

Recommendations 

The following recommendations are based on the information received in response 

to the Vegetation Management Order. The Commission has also drawn from the 

Blackout Report and the CNUC Final Vegetation Report. These recommendations were 

developed in collaborative discussions between the Commission staff and the state 

commissioners who participated in the initial review. 

1) The United States Congress should enact legislation to establish an Electric 

Reliability Organization and make its standards mandatory and enforceable, under federal 

oversight. Under such legislation, if the Commission were to approve a NERC standard, 

then it would be mandatory and enforceable for all transmission owners and operators. 

Mandatory, enforceable standards will result in greater compliance and, therefore reduce 

the likelihood of individual transmission line outages due to tree contacts, electric arcing, 

and fires, and thus improve local and regional grid reliability. 

2) Effective transmission vegetation management requires clear, unambiguous, 

enforceable standards that adequately describe the actions necessary by each responsible 

party. The NERC standard now being developed should serve this purpose. We 

recognize that the details of such standards must respect differing vegetative, climate, 

terrain, and other considerations, and thus may need to balance between results required 

and detailed prescriptions for how to manage vegetation, so it will be challenging to 

develop a clear, effective standard. But it must be done, and done as quickly as possible 

to assure that the nation’s customers and economy do not remain at risk to this known 

reliability threat. 

3) With respect to any jurisdiction issues that may arise involving vegetation 

management, it is important that state and federal regulators continue to coordinate so 

that jurisdictional considerations do not impede effective vegetation management.

4) As noted above, no reporting utility suggests that lack of financial resources or 

recovery of vegetation management expenses is an obstacle to the achievement of 

vegetation management goals. Nevertheless, both federal and state regulators should be 

sensitive to requests for rate adjustments in order to recover reasonable reliability and 

security related expenses such as those for vegetation management.34 

 34 See, e.g., Policy Statement on Matters Related to Bulk System Reliability, 107 
18 

5) The Commission should work with the CEQ and the federal land management 

agencies to streamline and better coordinate permitting and environmental requirements 

to facilitate better vegetation management without compromising environmental quality. 

While it is entirely appropriate that federal and state land managers protect the lands for 

which they have responsibility, the costs and consequences of vegetation-caused outages 

or blackouts are so high that agencies should reexamine these processes and requirements 

to see whether they need to be reformed. The Commission commits to work with the 

CEQ and other federal land management agencies on such an effort. Additionally, the 

CEQ could facilitate coordination with Native American Tribes for vegetation 

management on Native American tribal lands. 

6) Outages are often caused by trees that become hazardous to a line, as when a tree 

is dead or dying and has the potential to fall into a right-of-way and impact a line. These 

are a risk to reliability as long as the situation is not corrected, and so must be dealt with 

on a priority basis. State, local and federal land managers should recognize the 

importance of this situation and should develop priority or rush procedures to allow the 

utility to take prompt corrective action to mitigate these “danger” trees. 

7) Since numerous recent major blackouts have been caused by tree contacts with 

transmission lines, and the August 14, 2003 blackout was caused by trees that were 

managed on a five-year vegetation management cycle, the CNUC Final Vegetation 

Report concluded that a five-year cycle, while the industry norm, is not effective nor 

adequate for assuring transmission reliability across much of North America. For that 

reason, a shorter cycle should be used. While this and other enhanced vegetation 

management requirements suggested herein may increase utility costs, given the 

substantial and perhaps growing costs of reliability failures of the modern grid, the 

Commission and the states should encourage cost-benefit studies to examine the relative 

costs and benefits of current and more aggressive vegetation management practices. 

8) Transmission owners should work to remove the obstacles to effective vegetation 

management along transmission rights-of-way. This should include, at minimum: 

• Whenever possible, renegotiation of easement provisions where they do not grant 

adequate clearance and vegetation management rights. 

• Full exercise of all existing easement provisions and rights to assure adequate treepruning and clearing. 

• Where landowners or land managers have established lengthy permitting 

requirements or time-limited vegetation management operational windows, 

planning ahead to assure that the transmission owner or operator secures the 

 

FERC ¶ 61,052 at P 27-28 (2004). 
19 

needed permissions in a timely and predictable fashion. 

9) Variances in vegetation management practices may be resolved in the North 

American Electric Reliability Council (NERC) vegetation management standard 

development process; if they are not, the Commission may seek to convene the industry, 

states and other stakeholders to address the remaining. 

10) State regulators and the utility industry should approach NARUC, National 

Conference of State Legislators, and similar organizations to develop model guidelines 

and educational materials that can be used to help state and local officials understand the 

importance of this issue and how to manage it more effectively, through measures such as 

tree-pruning and tree-planting ordinances. If state legislation or changed agency rules are 

needed, utilities and state utility regulators should take the lead within each state to 

initiate the communications and cooperative discussions required. The Commission 

would support this effort, if requested. 
1 

Attachment A 

Companies that did not perform all identified vegetation management 

remediation by the June 14, 2004 reporting date 

• American Transmission Co. 

• Aquila, Inc. 

• Austin Energy 

• Basin Electric Power Cooperative 

• Black Hills Power, Inc. 

• Carolina Power and Light Co. 

• Central Hudson Gas and Electric Corp. 

• Central Louisiana Electric Company, 

Inc. 

• City of Tallahassee Electric Utility 

• Consolidated Edison Company of New 

York, Inc. 

• Dairyland Power Cooperative 

• Entergy Corp. 

• Georgia Transmission Corp. 

• Indiana-Kentucky Electric Corporation 

• International Transmission Co. 

• Lakeland Electric 

• Louisville Gas & Electric Co. 

• Lower Colorado River Authority 

Transmission Services Corp. 

• Montana-Dakota Utilities Co. 

• Municipal Electric Authority of Georgia 

• Nebraska Public Power District 

• New York Power Authority 

• NorthWestern Energy 

• Nstar Electric and Gas Corp. 

• Ohio Valley Electric Corp. 

• Oklahoma Gas & Electric Co. 

• PacifiCorp 

• PPL Electric Utility Corp. 

• Public Utility District No.1 of Chelan 

County 

• Puget Sound Energy, Inc. 

• Rappahannock Electric Cooperative 

• Santee Cooper Power 

• Seattle City Light 

• Sierra Pacific Power Co. 

• South Carolina Gas & Electric Co. 

• South Texas Electric Cooperative, Inc. 

• Texas Municipal Power Agency 

• Tucson Electric Power Co. 

• TXU Electric Delivery 

• Western Area Power Administration 

• Xcel Energy

 In some instances, the transmission owner/operator reported that remediation 

before the summer was not needed and would be completed as part of the regular 

vegetation management cycles later in the year. In other instances, the respondent states 

that there is no immediate threat to the line. Some stated that the work would be 

completed shortly after June 17 or as soon as possible. In at least one case, the required 

work was pending reaching agreement with a landowner. On August 26, 2004, Dairyland 

Power Cooperative filed an update with the Commission stating that all remediation has 

been completed.
2 

Attachment B 

Primary Contributors

LaChelle Brooks 

Saeed Farrokhpay 

Connie Hughes, Commissioner, New Jersey Board of Public Utilities 

Don Mason, Commissioner, Public Utilities Commission of Ohio 

Paul Massey 

Judith Ripley, Commissioner, Indiana Utility Regulatory Commission 

Alison Silverstein 

Christy Walsh 

Additional Staff Support

Charles Bayless 

Jonathan First 

Adam Hyde 

Daniel John 

William Longenecker 

Gary Nakarado 

Robert Novembri, Partner, CN Utility Consulting, Inc. 

Cynthia Pointer 

Christian Thoroughgood