Tree Trimming Safety Tree trimming operations require climbing, pruning, and felling trees. Hand and portable power tools such as loppers, trimmers, and chainsaws make the necessary cuts. Aerial lifts and chippers bring workers to the right height and clean up the worksite. The two leading causes of tree trimmer deaths are electrocutions and falls, so extra care and training is needed for work at heights and near power lines. Energized overhead or downed power lines can cause electrocutions if you come into direct or indirect contact with them. Don’t use conductive tools, ladders, or pole trimmers where they may contact overhead power...