A Midwestern utility combats pest problems and addresses hazard trees through scheduled inspections and a state-mandated trim cycle.
Dead, diseased and dying trees and power lines make poor neighbors. Industry estimates project that within the next few years, a shiny green beetle called the Emerald Ash Borer (EAB) could devastate the ash tree population in the Kansas City metropolitan region.
The EAB beetle, which was first discovered in southeastern Michigan in 2002, most likely migrated to the United States from Asia on solid-wood packing material carried in a cargo ship or airplane. Since that time, the beetle migrated to Ohio, Indiana, Maryland, Illinois, Pennsylvania, West Virginia, Wisconsin and, most recently, Missouri.
Ash trees are the lone host for this beetle. While the adult beetles nibble on the foliage and cause insignificant damage to the ash trees, the larvae inflict considerable harm. The female insects lay eggs on the bark of the tree in the winter, and in the spring, their offspring eat away the nutrients of the tree. By feeding on the inner bark of the ash trees, the trees can no longer transport water or nutrients. Once a tree is infected, very little can be done. Within a year, the tree will begin to exhibit symptoms and slowly begin to die.
Since the pest was first discovered, it has killed 20 million ash trees across the United States and many more in Canada. The disease is slowly spreading across the country at a rate of about 12 miles per year.
While none of the beetles have been spotted yet in the Kansas City area, they were discovered about three hours southeast of the city in Cape Girardeau, Missouri, last fall. While no one is certain when EAB will arrive in Kansas City, Kansas City Power & Light (Kansas City, Missouri) has developed an action plan to deal with the potential outcome.
This advanced planning has become especially important since KCP&L purchased neighboring utility Aquila last July. The utility company now serves twice its geographical service area, and the combined company now has a unified standard vegetation management program as well as a cohesive strategy to prepare for the EAB invasion.
Plan of Action
About 10,000 ash trees line the streets in the Kansas City metropolitan area, and thousands more are growing in home-owners' yards, says Helene Miller, the Missouri Department of Conservation District forester.
While KCP&L is in no hurry for the arrival of the EAB, the utility has taken steps to be ready when the pest migrates to the area. For example, KCP&L resides on statewide EAB suppression teams. Their responsibilities include training in the identification and reporting of the insect and/or infested trees. Infested tree trunks and limbs within 10 ft of power lines are scheduled for clearing. The teams also work collaboratively with other agencies to schedule and clear infected ash trees they have discovered.
KCP&L is also bracing for the EAB invasion by sticking to an established trim cycle. By moving to a cyclical approach, the utility has saved money and is on track to comply with state regulations and standards. In addition, the utility is a step ahead while awaiting the EAB's arrival.
For the last seven years, KCP&L has partnered with Environmental Consultants Inc. (Southampton, Pennsylvania) on its distribution vegetation management program. ECI, which serves as a mediator among the tree contractors, the customers and KCP&L, plans and schedules individual circuits to be trimmed and patrolled, monitors the contractors' work and assesses contractor performance quarterly.
Through the mid-cycle patrols, ECI work planners patrol every mile of every circuit. These degreed foresters determine when individual tree conditions pose a public safety or service reliability concern before the next scheduled return date. At the same time, the tree crews are on the lookout for any sign of EAB infestation.
In addition to taking proactive steps to control the spread of disease from the EAB, KCP&L also takes a rearview mirror approach in its vegetation management program. The utility sponsors a monthly customer care meeting to evaluate neighborhoods or entire circuits that are experiencing poorer-than-normal system reliability using data from an outage management system. ECI also investigates every tree-related outage that occurs on its primary lines. During this investigation, ECI determines the date of the outage, whether or not it was preventable and notes the tree species.
The outage-cause analysis will become especially important with the upcoming EAB invasion, in which KCP&L and ECI will be able to identify the insect more quickly and hopefully slow down its infestation rate.
Besides early detection and eradication, a proactive approach to control the spread of the EAB is through pesticides. According to a 2004 study, the effectiveness of this treatment can vary widely depending upon the size of the tree, the extent of damage and the site conditions. The study also found that it is just as effective to spray the tree's canopy as to spray the entire tree.
One of the most thoroughly tested pesticides is an active ingredient compound called imidacloprid. The active ingredient is sold under trade names Kohinor, Admire, Advantage, Gaucho, Merit, Confidor, Hachikusan, Premise, Prothor, and Winner in both professional and over-the-counter pesticides. Imidacloprid kills insects as they bore through trees, and it is usually applied once a year by pouring or injecting the pesticide into soil surrounding affected trees.
While some entities have had some success with inoculating trees, ultimately, it has claimed the life of many trees. At this time, KCP&L is not using pesticides to prevent EAB infestation in the Kansas City area.
Preventing the Spread of EAB
Regardless of the means of controlling the spread of disease, utilities will need to take action in the near future. If artificial movement of EAB is not prevented, it will quickly surpass infestation projections.
EAB can be spread in any ash wood that has not been treated to prevent EAB survival including ash logs, firewood and nursery stock. Treatments to eliminate EAB from these materials include debarking (including outer ½-inch of sapwood), chipping to less than 1-inch diameter and kiln drying for 75 minutes at a minimum temperature of 160°F at the center of the wood.
Experts say the disease may have spread rapidly, because the diseased trees were sold as firewood rather than being quarantined. To prevent this from happening again, regulatory agencies have enforced quarantines and are enforcing fines to prevent infested ash trees, logs or firewood out of regions hit by the EAB. Once they have been infected, the only way to handle the situation is to remove the tree, chip up the brush and prohibit anyone from moving the firewood.
Through preventive maintenance and mid-cycle follow up, KCP&L, ECI and the contractors hope to control the spread of the EAB and identify any infested trees before the disease takes down trees across the region.
Gary O'Neil (firstname.lastname@example.org) is the superintendent of vegetation management for KCP&L. He is a 30-year utility arboriculture industry veteran.
Geoff Vossen (Geoffrey.email@example.com) is the distribution system arborist with ECI and has been with the company for seven years.
EAB FAST FACTS
- Bug appearance
The adult Emerald Ash Borer is about a half-inch long, is metallic green and has purple abdominal segments below its wings. The larva is white, legless and features bell-shaped flat body segments.
- Signs and symptoms
The top one-third of the tree's canopy dies first, and then the destruction progresses downward until the tree is completely bare of leaves.
- Bark damage
Infested trees will have vertical splits on the bark as well as D-shaped exit holes.
Source: Michigan State University
FOR MORE INFORMATION
The USDA Forest Service, the Michigan Department of Agriculture, the Michigan Department of Natural Resources, USDA Animal and Plant Health Inspection Service, Michigan State University, Purdue University and Ohio State University collaborated on a Web site with the latest news and resources on the Emerald Ash Borer. Visit www.emeraldashborer.info for photos of the bug and of the destruction it causes. If you suspect EAB infestation, you can also call (866) 322-4512.