Daniel L. Cassens

Implications of Branch Strength Loss in Silver Maple Trees Converted from Round-over to V-trims During Electrical Line Clearance Operations

Publisher Summary Historically, trees growing beneath powerlines were often subjected to round-over trimming where heading cuts were used to maintain conductor clearances. An extensive flush of watersprout growth typically occurs after round-overs and trees rapidly regain their original heights. Many utilities have adopted V-trimming where the center portion of the canopy is trimmed while the exterior portion remains. Trees converted from round-overs to V-trims could develop a canopy of watersprouts growing on parent stems with a high probability of decay. This chapter determines if the conversion from round-over to V-trimming predisposes trees to failure. Silver maple ( Acer saccharinum L.) watersprouts were mechanically pulled from converted trees. In more than 20% of the sampled watersprouts, the leaders broke before the watersprouts. The conversion from round-over to V-trimming appears to predispose parent stems in silver maple trees to failures. Managers should consider the long-term consequences of converting from roundover trimming to V-trimming and decide if other actions are appropriate, including the removal of trees with a history of multiple cycles of round-over trimming.