According to ASU's climatologist Nancy Selover, shaded parking can make a 60-70 degree difference in surface temperatures inside a car after just an hour parked in the heat. A car in the shade might rise in temperature to 115, while in the sun it can reach 180 degrees. I find when I go grocery shopping, there are only a few spaces that have any shade!
According to the EPA, asphalt will absorb the heat from the sun rays and be 50-90 hotter than the air, and raise the temperature of the city at night to be as much as 22 degrees hotter than less developed regions. This creates a greater demand for electricity and energy, more pollution, decrease in rainfall.
Trees provide shade, absorb carbon dioxide and provide oxygen, wildlife habitat, buffer noise pollution, and are more visually appealing. Studies by Urban Greening Research has found large trees do NOT provide a screen for crime, but reduces criminal activity such as graffiti, vandalism, littering, aggression, and violence. It is found to create a more reassuring environment. People are more aware of their surroundings and feel safe with urban forestry. What makes a difference in the beauty and attraction of a city, is their Landscape Architecture Department. I think this would be a great reputation to gain, that we in Mesa, are "green."