<Li> The city of Visalia, California has implemented a street tree ordinance intended to promote and regulate the planting, maintenance, and protection of street trees within the city . Their ordinance does not allow street trees to be altered, pruned or removed . Street trees are also protected during construction . </Li> <Ul> <Li> A large percentage of people who live in urban areas have access to parks and gardens in their areas, which are probably the only connections they have with nature . A study shows that having contact with nature helps promote our health and well - being . People who had access to gardens or parks were found to be healthier than those who did not . </Li> <Li> Another study done investigating whether or not the viewing of natural scenery may influence the recoveries of people from undergoing surgeries, found that people who had a window with a scenic view had shorter postoperative hospital stays and fewer negative comments from nurses . </Li> </Ul> <Li> A large percentage of people who live in urban areas have access to parks and gardens in their areas, which are probably the only connections they have with nature . A study shows that having contact with nature helps promote our health and well - being . People who had access to gardens or parks were found to be healthier than those who did not . </Li> <Li> Another study done investigating whether or not the viewing of natural scenery may influence the recoveries of people from undergoing surgeries, found that people who had a window with a scenic view had shorter postoperative hospital stays and fewer negative comments from nurses . </Li>

Which of the following is not a valid explanation of the urban heat island effect