Hydro one considers vegetation management to be a vital aspect of providing cost-effective reliable service to its customers. Tree removal, pruning, brush control, customer notification, customer requests, patrols, storm restoration, asset condition surveys and new right-of-way (ROW) clearing are some of its areas of responsibility, all of which happen around a huge number of assets.

Hydro One (Ontario, Canada) has 203,000 acres (82,200 hectares) of transmission ROW; 47,000 towers; 520,000 transformers; 1.6 million low-voltage wood poles and structures; 1035 distribution and regulating stations; and 274 transmission stations and switching stations. The Hydro One Forestry Services department removes an average of 215,000 trees, prunes 285,000 trees per year, and controls brush on 25,000 acres (10,100 hectares) of ROW per year on the distribution system and 30,000 acres (12,150 hectares) of ROW per year on the transmission system.

Hydro One is consistently open to trying new or different ways to get the job done more cost-effectively. Over the last five years, the utility has been working with equipment manufacturers to design tracked brush grinders capable of handling rough terrain and heavy brush conditions. In heavy-density brush conditions, this is a safe and cost-effective method of controlling brush on both the distribution and transmission systems. This equipment has the ability to actually dig out and mulch the root systems, resulting in long-term control when compared to traditional mechanical cutters, which just cut off the stem leaving the stump to quickly sucker back.

Another mechanical innovation at the utility is the use of feller-bunchers for tree removal on new and established ROW. Compared to manual tree removal this equipment is cost-effective when a large number of removals are required along a ROW.

Part of Hydro One's productivity improvement efforts includes standardizing its geographic information system (GIS) on the ESRI platform, which incorporates Transmission Line GIS, a geographically referenced video system to support its vegetation management module. This GIS module has been developed into a state-of-the-art vegetation management application for Hydro One's transmission corridors. The Forestry Services department has also developed a Web-based Forestry Management System, which allows for online work reporting and provides our 36 forestry technicians with field access to all customer and property owner data via portable tablet computers. This system also serves as a data warehouse for all cost, productivity, asset-condition assessment and outage data, which can quickly be referenced by circuit.


The backbone of Hydro One's vegetation management team is its 288 highly skilled forestry journeymen, all of whom have completed a four-year apprenticeship; 36 forestry technicians; and 16 district forestry front line managers. The Hydro One apprenticeship program was the blueprint used to develop the Ontario Ministry of Trades Colleges and Universities Utility Arborist Apprenticeship program, which is being rolled out this year and is a major step forward for Ontario's utility arborist trade. Mike Greer from Hydro One's Training department chairs the government steering committee that developed the utility arborist program.

Over the last three years, Hydro One has embarked on a major hiring and training program with 130 new apprentices in the system, which will meet the requirements of our expanding work program as we target to achieve a six-year distribution cycle in the southern parts of the province and eight years in the north, where growth rates are slower. Achieving these cycle targets will result in improved system reliability and safety for our customers.

The majority of herbicide application on the distribution system is done as a low-volume backpack application to stumps and brush stubble after the brush and trees are cut. Garlon 4 from Dow AgroSciences is the herbicide of choice and is extremely effective on a wide variety of tree species. Selective application with low-volume backpack sprayers containing a mixture of Garlon 4 and mineral oil ensures maximum root kill with minimal spray drift. On the transmission system in southern Ontario, the main tool used for brush control is low-volume backpack Garlon applied to the bottom 12 inches (30 cm) of the stems. Brush densities and heights are low enough on these ROW to make this the most selective and cost-effective treatment method.

This year could prove a real challenge to the Forestry Services department as the Emerald Ash Borer (EAB) beetle, a recent arrival to Canada, has killed thousands of ash trees in southwestern Ontario. The movement of infested firewood has been the main culprit in the spread of the insect and the Canadian Food Inspection Agency (CFIA) has imposed quarantines, with strict penalties attached, prohibiting the transport of firewood outside of EAB-known regions. The CFIA has cut a 12-mile (20-km)-wide ash-free buffer zone close to the Canada-U.S. border to try to prevent the EAB from moving further north. All of our forestry technicians are aware of the problem insect and have received training from CFIA to be able to report any new sites where the EAB is discovered. In addition, the Asian long-horned beetle, another damaging insect to all hardwoods, was recently discovered in the greater Toronto area and the CFIA has put a 2-mile (3-km)-radius quarantine zone in place in an attempt to control the spread of the beetle. At present, there are no known useful insecticides or natural enemies to control the pests.

Going forward, Hydro One anticipates substantial changes coming in the area of vegetation management for utilities. Chemical giants such as BASF, Dupont and Dow continue to refine herbicides and pesticides, making them more effective while improving environmental safety. Both the Federal Energy Regulatory Commission and the North American Electric Reliability Council will remain proactive in monitoring activities and the new UAA-supported A300 ANSI Integrated Vegetation Management standard, which sets out useful guidelines for service providers, should streamline field efforts and help maximize our return on resources expended.

Glen Parsneau is a provincial system forester with Hydro One. glen.parsneau@HydroOne.com