SISTERS, OR -- The final phase of the Highway 20 tree removal process starts today. ODOT’s Peter Murphy says they used an herbicide along the highway that got into trees. He says last year ODOT had to cut down 21-hundred trees, using some for wood products and leaving some for wildlife habitat. Murphy says starting today ODOT will be remove stumps along both sides of Highway 20 on the west side of Sisters to eliminate traffic hazards. The work could take six weeks and  everyone asked to drive carefully through the area.