Beetles destroyed millions of trees in British Columbia, and about 10 to 12 million dead trees are adjacent to high-voltage power lines. Beyond the threat to public safety and the reduction in reliability, tree failure and power line contact could ignite a wildfire, setting ablaze hectares of dead and tinder dry standing trees. Conversely, fires ignited by natural or man-made sources could burn down kilometers of power lines along forested roads.
Canada is currently experiencing its largest mountain pine beetle outbreak in its history, which poses a threat to BC Hydro's electrical facilities throughout the province. As many as 20 million hectares (49.4 million acres) may be infested with the mountain pine beetle (Dendroctonus ponderosae). The beetles destroy the trees by introducing a blue stain fungus into the sapwood that prevents the tree from repelling and killing the attacking beetles with pitch flow. It also blocks water and nutrient translocation within the tree. The joint action of larval feeding and fungal colonization kills the host tree within a few weeks of successful attack.
Under normal conditions, these insects play an important role in the life cycle of a forest. They attack old or weakened trees, speeding the development of a younger forest. However, unusually hot, dry summers and mild winters in central British Columbia during the last few years, along with forests filled with mature lodgepole pine, have led to an epidemic. Traditionally, three weeks of temperatures below -10°F (-23°C) were considered sufficient to keep this beetle in check. It has been more than nine years since the area has experienced these winter temperatures.
Global warming may be a culprit in the milder winters and the onslaught of the mountain pine beetles. To date, beetles have destroyed millions of lodgepole pines, British Columbia's most commercially harvested tree. Forestry sources estimate that 95% of the province's lodgepole pines will be dead by 2011. The pandemic is now advancing through the southern parts of the province, and the beetles are now attacking the ponderosa pine, the dominant pine species in the area. More than 9.2 million hectares (22.7 million acres) were in red-attack stage in 2007 as a result of the mountain pine beetle. The red-attack category involves all trees that are red or gray (longest dead).
EFFECT ON BC HYDRO POWER SYSTEM
As a result of the beetle attack, BC Hydro is implementing the largest hazard-tree-abatement program in its history. The BC Hydro Forest Health Issues and Projects (FHIP) team, led by Rick Walters, manager, and James McKendry and Jeff Connors, vegetation coordinators, has been working to reduce the effect of this epidemic since July 2005. To date, the team has managed to reduce the hazard by 1.5 million trees. In addition, Brian Fisher, provincial distribution vegetation management manager, Duncan Isberg, distribution vegetation management strategic planner and Tom Wells, BC Transmission Corp.'s vegetation manager, meet regularly with the Ministry of Forests' head office personnel to attempt to coordinate efforts and to maximize both risk reduction and fiber utilization.
BC Hydro's nominal clearance between power lines and forest is 3 m to 5 m (10 ft to 16 ft). Dead pines stand 20 m to 25 m (60 ft to 80 ft) tall and are often on both sides of the road. Forestry sources say that these infested trees will start to fail within 6 to 10 years and will virtually all be down within 30 years.
Overlaying BC Hydro line maps on forest infestation maps shows about 5000 km (3200 miles) of BC Hydro distribution line are threatened by dead trees. Using a conservative cost per outage of US$2000, BC Hydro estimates that it could face as much $1 billion in repair costs from individual strikes without its program in place. This figure doesn't even take into account the potential for fire-caused outages.
Due to the scale and dynamic nature of this epidemic, the BC Hydro team has used several hazard-abatement tactics and tools during the program. The team has consulted and contracted professional foresters, biologists, archaeologists, loggers, certified utility arborists and utility specialists. It also has coordinated efforts and worked in conjunction with the Ministry of Forests and Range, Ministry of Transportation, Ministry of Environment, municipalities, major forest licensees and small-scale salvage programs.
The mountain pine beetle hazard-abatement program began with an inventory analysis and assessment primarily to map the magnitude of the problem and identify the worst areas to address first. Once these areas were identified, a team of consultants, foresters and archaeologists proceed to the target areas to obtain consent, prepare forestry tenure applications and to confirm that there are no other conflicting issues with heritage or historic sites.
The BC Hydro team then proceeds with local work contracts or public tenders to fell the trees. This can include single-tree felling by certified utility arborists, logging private property or logging provincial crown property. The goals are to reduce the threat of public safety, to decrease damage to the facilities and risk of fire, and to increase system reliability for BC Hydro customers. A secondary goal is to maximize fiber recovery and minimize fuel loading from debris.
With the secondary goal in mind, a variety of options are discussed with the landowners prior to commencing the tree work. The utility often offers funds to the property owners to buy the wood from them, take the trees down and deliver it to a local mill. Many people with larger parcels of land have become overwhelmed by the numbers of trees on their private property and don't have the means or forestry knowledge to deal with this.
BC Hydro is also working with municipalities to attempt to maximize the cooperative efforts and secure the residential communities first. Many communities have timber permits and also have a “Fire Smart” committee to look at reducing fire risks. BC Hydro contractor crews will work with the communities to fell trees, which the community will then salvage. Often, the proceeds from this community timber sale will be used to help purchase new trees for the community.
So far the focus has been in the northern interior regions of British Columbia. The results from the most recent southern interior assessment data suggests the problem is equally as great in the southern regions with an added twist coming from spruce and fir beetles and the fact that the mountain pine beetle is infesting ponderosa pine as well as lodgepole.
What started as a project to address the initial mountain pine beetle program has now resulted in the establishment of the FHIP department within BC Hydro's Distribution Vegetation Management department. The primary issues that differentiate FHIP issues from the core vegetation-management program are a consistent focus on dead trees and attempts to log and use the fiber as much as possible. The core program seldom interfaces with the Forest Ministry, whereas FHIP does so on a daily basis.
An interesting aside to all of this is that it is becoming apparent that the demand for fiber from these dead trees is insufficient to allow them all to be harvested and used before they deteriorate. Only a portion of the trees that are near BC Hydro lines are usable as saw logs. Some have now deteriorated to where they have pulp value only. There are several studies underway to look at whether the end use for many of these trees may not be as biomass fuel for electrical generation.
The FHIP program is designed to continue for a minimum of a decade, addressing first trees within communities and, secondly, timber stands on a “worst first” basis. The potential for other forest health pandemics (Douglas fir bark beetle, spruce bud worm, laminate root rot) may push the need for these special approaches. Conceivably, this program will continue forward for many years in an attempt to ensure reliable delivery of power to the people of British Columbia and stay ahead of pathogen-caused tree failure.
Jeff Connors is the vegetation coordinator in the northern interior for BC Hydro, where he works to reduce the impact of the mountain pine beetle epidemic along power line corridors. Connors is an ISA-certified arborist and utility arborist. He has a BSc degree in forestry from the University of New Brunswick. Connors is registered with the BC Forest professionals as a forester in training. Jeff.Connors@bchydro.bc.ca
Brian Fisher is the manager of distribution vegetation management for BC Hydro. Fisher is a certified arborist and a registered professional biologist for the province of British Columbia. Fisher is past member of both the Certified Arborist Test Committee and the Utility Specialist Test Committee. He is past president of the International Utility Arborist Association and a board member of the Tree Canada Foundation. Brian.Fisher@bchydro.bc.ca
The following websites will provide additional resources on this topic.
National Resources Canada:
Government of British Columbia homepage: