With the ongoing drought and heat, it is important to water your trees and shrubs in the landscape and along the neighborhood streets for survival.  Place your hose close to the base of the tree and let a small stream of water run for an hour or longer, about 10 gallons would help tremendously.  Doing this once every couple of weeks will help them get through the summer drought until rain hopefully returns this fall.

Check out the following article for more information.
http://mdc.mo.gov/newsroom/water-shade-trees-avoid-drought-stress