With the recent hot weather, more trees in the region are starting to once again show signs of drought stress. Branches are losing their leaves, many trees are showing exit holes from recent borer attacks, and still many more are just dying outright and needing to be removed. All of these signs of tree sickness and mortality are a cumulating of the past several years of hot temperatures, very little rain, and high, hot winds adding to the drying out process. The ground just finally ran out of water, and what resources the trees had to help them through these last couple of years have now weakened them and opened them up to insect infestation and disease pressure.
The absolutely best thing you can do for your trees at this time is to water them in excess to your lawn. When you water your lawn, it normally is enough to keep your grass green, but the lawn uses the valuable water, leaving little or none to make it down deeper in the soil to the tree. To give your tree the best environment to stay healthy, mulch around the base of your tree. Out to the drip line of a tree would be best for its health, but since most of the time that would leave you with no lawn, two to four feet out from the trunk will be ok. This will help keep the moisture where the tree can get it, and also reduce the competition between your lawn and tree. The next action you will need to do is water. Hooking up a drip line around your tree is the most convenient way to achieve this. There are no hoses to drag around, and not a lot of extra effort after set up, but for some lawn arrangements, this is not feasible. The next way would be to just leave your hose on at a slow trickle for several hours. If neither of these will work for your situation, then getting a five gallon bucket and putting a hole close to the base of the bucket, filling it with water and setting it by the tree works just as well. After watering, test the soil in several spots around the tree with a long screwdriver or piece of re-bar. Push it into the ground as far as it will go. When you hit dry soil, it will stop. Pull out of the ground and measure how far it went in. Your tree needs 12-18 inches of moist soil to be watered well. If you do not have that, water more until you reach the desired depth. By doing this every 2 to 3 weeks, you will be ensuring that you are giving your tree the best chance of survival in the drought.