The City of The Dalles is asking citizens to make a special effort to prevent unsightly damage to street trees that have low hanging branches.   The Dalles Municipal Code requires all trees growing near a sidewalk, street, or alley to be trimmed so the limbs and branches are not less than nine feet above the sidewalk and 14 feet above the street, allowing safe passage for pedestrians and large vehicles.  Trimming before a collision breaks branches is healthier for trees.  Tree trimming also prevents damage to tall vehicles like recreational vehicles, garbage trucks and school buses.