Cincinnati Gas and Electric contracts a tree service company to prune limbs away from power lines on a systematic basis. It is important to keep limbs from interfering with the wires because it can present dangerous and costly problems. They require 3.5 feet of clearance on either side of secondary wires and 7 feet clearance on either side of primary wires. This can result in some unsightly tree crowns depending on the species and growth habit of the tree, even with proper pruning practices. Urban forestry works with CG&E and their contractors to minimize any potential negative affects by inspecting each street tree before work is performed and discussing pruning strategies.