Unless they are newly planted trees, this year, I wouldn't worry... They may drop leaves a bit early but will be fine if they have become established over the past year or so. If they are recently planted, say this past spring, here is neat trick a landscaper friend showed me years ago. Buy lengths of 2 inch PVC conduit. Cut them into 2 or 3 foot sections and drill multiple quarter to half inch holes in the lower half of one side. Pound 2 or 3 pieces into the ground about 12 inches from the trunk; spaced out around trunk. Slide hose into the PVC and allow a slow but steady stream on water into the tube. I found it is best to get a 2 inch round pole like piece of wood or a metal pipe and use that to form the hole for the PVC. I've used this technique for years when needed; even for new shrubs