Crews of Westar-hired tree-trimmers are back in force in Lawrence, and they’re growing in number faster than a well-watered willow.

Workers with Wright Tree Service deal with rain and traffic as they trim trees near the intersection of 23rd Street and Massachusetts St. Monday, Dec. 19, 2011. Westar has contracted with Wright to trim back trees near power lines in the city.

Westar Energy officials have more than doubled the number of tree-trimming crews in the city as part of a new four-year program to trim trees along 870 miles of electrical lines in the city, the company said Tuesday. Property owners who live near power lines should expect a Westar-hired crew to be along every four years, rather than the more standard time interval of every 8 to 10 years.

“This program will take a more proactive approach,” said Jeff Martin, director of reliability for Westar Energy. “Lawrence does have a lot of tree-related issues.”

Westar will divide the city into four areas, with dividing lines along Iowa Street and 15th Street. Crews currently are in the southeast area of the city, including along 23rd Street and soon will be moving into areas along 19th Street.

Westar estimates that it will take the approximately 10 crews assigned to the program a year to go through each quadrant. Next year, Westar expects crews to be in the southwest area of the city, then the northwest area, and the four-year cycle will end in the northeast section of Lawrence. The program then will start all over again.

Westar estimates that 16 percent of all power outages in Lawrence are directly related to issues with trees near power lines. After the program is fully implemented, Westar expects the number of power outages will decline by 30 percent, in part because crews will be able to better visually inspect all power lines.

“This is really about trying to stop outages before they happen,” said Chad Luce, manager of customer and community relations for Westar.

But the tree-trimming in past years has created concern from property owners who differ with Westar’s assessment of how much a tree needs to be trimmed or whether it must be taken down entirely. Westar has broad powers to remove trees — even trees in city parks and others owned by the city — if the trees are in a utility easement.

Luce said Westar subscribes to best practices for tree-trimming and has won recognition within the utility industry for its tree management program. Westar officials are hoping that the more frequent pruning will mean less severe trimming in the future.

Westar also plans to notify property owners along power lines at least two weeks in advance of tree-trimming crews entering their neighborhoods. Westar plans to hang informational packets on the doors of properties that will be affected, and they also will contact neighborhood associations and offer to host informational meetings before cutting begins.

Lawrence is the second city in the state where Westar has implemented the more frequent tree-trimming program. The company started the program in Wichita last year.

The program aims to trim trees along every power line in the city, except for service lines that run directly from a pole to an individual’s home. Keeping trees clear from those lines continues to be the responsibility of property owners.