What is Wrong With All Our Trees?

I have had literally a hundred calls about trees in just the four short weeks I have been in Williamson County. Many of those calls concern Oak Wilt and its devastation of our oak tree population but at least half the calls are for trees that don’t get oak wilt like Bradford Pear, Burr Oak, Sycamore, etc. Some of the calls have been about Red Oaks or Live Oaks that don’t have oak wilt but for some reason they just look terrible!! It is not unusual for these sick trees to have their leaves falling off or having a dull grey to bronze look to their leaves.
What’s wrong with all these trees? Simply put it is the driest summer on record and our trees are showing us the effect of continual hot, dry weather. Let me put it in perspective. Our evapotranspiration rates this summer were averaging 0.4 inches of water a day with high temperatures in the 105º range. Evapotranspiration is water lost through the plant to the atmosphere, but it is used by the plant to cool itself. When a plant cannot take in enough water to transpire (sweat in human terms) it can “burn” in these high temperatures. Now I know that most of you will immediately say “yes but I ran my sprinkler system every week.” I am sure you did, but you also had turf and that turf captured all the water with very little if any going to the tree. I have used a sharpshooter shovel around many of these sick trees to demonstrate that the effective water penetration is only 2-3 inches in many cases. If you still don’t believe me just remember that a mature peach tree needs 80 gallons of water per day and a mature pecan tree needs 222 gallons per day. Raise your hand if any of you even came close to this??
So you can see that our “hottest summer on record” has hurt our trees and shown us as humans that we don’t know how to water. Trees need deep watering and the only way to do that is to put a water hose on a slow trickle and leave it for hours under our trees, moving it occasionally. But all is not lost, most if not all these trees will overcome our lack of understanding and forgive us by putting on lots of new growth this year and next!