The Knox County Regional Airport hired a contractor to cut trees surrounding the airport to improve visibility, a project that has been ongoing for years, said Airport Manager Jeffrey Northgraves.

Some of the trees being cut and topped are on the property of surrounding homeowners, and the county previously negotiated a deal with property owners to compensate them for leveling the trees by right of eminent domain.

The Knox County Commission voted to approve deals with 14 property owners in June 2013.

About 20 percent of the trees to be removed is decided by private property owners, independent of the county's work, although the same contractor is hired for both jobs, said Northgraves.

Light poles are also erected in certain areas to improve visibility for airplane pilots.

Northgraves described the clearing as general maintenance.

The project, costing $545,000, is expected to be complete by the end of September. Ninety percent of the cost is paid for by Federal Aviation Administration improvement grants, with the remaining 10 percent of the cost covered by the state and county.

Northgraves said in June 2013 during a county commissioners' meeting that aircraft already has the right to fly over properties and the Federal Aviation Administration owns the airspace, but the county needs permission to go onto private land and remove trees that are penetrating the airspace or within 15 feet of the boundary.

Northgraves described air space as an imaginary surface that trees and structures cannot penetrate and obstruct flight paths.

Courier Publications' reporter Juliette Laaka can be reached at 594-4401 ext. 118 or via email at jlaaka@courierpublicationsllc.com.