Log Debarkers Used To Reduce Tree Removal Costs and
Increase Value of Trees Affected by Emerald Ash Borer
Holly, MI — The USDA Forest Service and several State and private agencies took part in a demonstration and applied research project to evaluate using commercial log debarking equipment to reduce the costs of emerald ash borer (EAB) eradication and disposal of EAB-infested trees. The debarking equipment removes the bark and about 1 inch of the outer portion of the log, interrupting the EAB life cycle. Following debarking, scientists examined the logs to determine if any EAB remained. While results are still being analyzed, the potential benefits can mean millions of dollars in savings during infested tree disposal.
The emerald ash borer is an insect that threatens ash trees. This insect is so destructive that the State Departments of Agriculture in Michigan , Ohio , and Indiana have placed a ban on the transportation of ash in certain areas to slow the spread of the insect to uninfested areas. Millions of dollars have been spent in these States to locate and destroy EAB.
If scientists find that debarking infested ash trees is a viable option, trees can be debarked onsite and transported outside the quarantine zone to be processed into lumber, furniture, and other wood products. Currently, infested ash trees and all other ash trees within ½ mile are completely destroyed onsite or are utilized within the quarantine area, often in low-value applications.
“I see no reason why this idea couldn’t be adapted to a commercial situation and quickly put out into the field,” said Andy Sabula, Forest Industrial Specialist for the Ohio Division of Forestry.
Personnel from the State Divisions of Forestry and the USDA Forest Service have been searching for ways to reduce disposal costs and provide alternate markets for ash trees infested with EAB.
The idea to experiment with debarking came about as a result of conversations between USDA Forest Service Morgantown Field Office Utilization Specialist Al Steele and Sabula. Noting that EAB live only in the bark and outer portion of the tree, they wondered whether a portable version of standard debarking equipment used at sawmills could be utilized to remove the infected material on the outside of the log, allowing the remaining portion of the log to be safely transported anywhere and processed normally.
Steele, who coordinated the event, said that the debarking project was a success because of the textbook example of interorganizational cooperation.
“This event particularly highlights the important role that the private sector must play in addressing the EAB issue,” he added.
The demonstration was a collaborative effort between the USDA Forest Service Northeastern Area’s Wood Education and Resource Center , Ohio Division of Forestry, USDA Forest Service North Central Research Station (Lansing), Michigan State University , Maumee Valley RC&D, debarking equipment manufacturer Morbark, and Barry Bass, president of Bedrock Express, a wholesale distributor of landscaping supplies.
Morbark, a Michigan-based forestry equipment company, gave generously of its time to ensure that the technical aspects of the debarking demo worked flawlessly. "Morbark delivered on their promise to produce smooth, bark-free logs. [The] logs looked like they had been turned on a lathe, which is of course how baseball bats are made,” Steele said.
The emerald ash borer matures in the bark and outer ½ inch of the cambial layer of the tree. Its larval tunnels disrupt the flow of nutrients and water up and down the tree, eventually causing death. By debarking the sawlogs in the field, the EAB larvae are destroyed, eliminating further spread of the pest.
Failure to contain this pest is feared to have very significant consequences, including the loss of billions of dollars worth of commercially valuable ash trees from the Dakotas to Maine , dramatic changes to the ecology of forests where ash occurs, and up to $1,000 per-tree-removal costs for trees dying in urban areas and near residences.
Ohio Department of Agriculture officials estimate that 75 percent of the entire EAB program cost is associated with disposal of these potentially infested trees.