Chicagoans will be able to drop off their Christmas trees at 23 locations between 9 a.m. and 2 p.m. Saturday. The trees will be mulched, and residents can bring the mulch home if they wish. The goal is to keep the trees -- which weigh an average of 20 pounds and take up about as much space as an old washing machine -- out of landfills, said a spokesman for the city's Department of Streets and Sanitation. Early arrivals will receive free blue bags and seedlings. Last year, about 12,000 trees were recycled.