The county is now recommending a 16' clearance height of tree branches that hang over the street to accommodate larger trash pickup vehicles. Branches scrape the trucks, damaging their paint, and can break, causing a hazard to pedestrians and drivers. If your oak tree extends over the sidewalk, it should be trimmed up to at least an 8' clearance, and 16' over the street. Click here for information on how to properly prune trees.