Yes, the City requires you to trim or cut down trees that pose a danger of falling or obstruct the vision of motorists. Shrubs which boarder a yard along a sidewalk should also be kept clear from obstructing vehicular traffic or encroaching onto a sidewalk. Trim overgrown grass and vegetation or remove the grass and clippings from your property. Clear brush, weeds and dry grass from 30 to 100 feet around your home. The Mill Valley Fire Department can help you determine the exact distance based on slope, wind, neighborhood density, house construction, etc.