Urban forestry means planting and taking care of trees in cities and towns. Trees are important for a number of reasons in cities. They can help keep the air cleaner and healthier to breathe, help make places cooler, provide cooler air for us to enjoy, and make a city more beautiful. Urban foresters take care of the trees in cities by making sure the trees get water, taking care of any insects or diseases they might have, andreplace them if they die or get too old.