Heat Waves: Worse Than Miserable

Yesterday, we broke our local all-time record for 100F degree temperatures in a calendar year—50 days—and the end is not yet in sight. Down in the Texas Hill Country, artist Pablo Solomon recently reported 63 days above the century mark—and no rain for nine months!

The heat wave of 2011—the hottest summer in the state's recorded history—is beyond just miserable. A nearby wildlife-rehabilitation facility is now caring for more than 100 baby Mississippi kites that had bailed out of their nests because they were roasting up in the treetops. In the opposite direction, the ground has baked so deep that, in our back yard, we discovered a pocket gopher sprawled on the grass beneath an old oak tree that had just been watered. The critter appeared to be luxuriating on the damp soil.

And, oh, those poor trees. Unlike birds and gophers, trees can't go anywhere during unremitting heat waves. As the soil heats up and dries out, a tree's delicate feeder roots dry out too. And the soil doesn't have to dry  very deeply to start causing real damage.

Most of a tree's vital feeder roots are within 6 to 20 inches beneath the surface, spread out up to three times the diameter of the tree's drip zone—the outer edge of its branches. (Deeper "perennial" roots merely anchor the plant to the ground.) All feeder roots are important, but those within the drip zone are absolutely critical.

So I soak that old oak's "critical root zone" during these miserably hot, dry days, making sure the delicate subterranean feeder system doesn't overheat and desiccate. Thus far, the heat-beleaguered tree has hung onto its sparse canopy foliage, while other trees around town have already died. So I assume the oak appreciates my efforts with the water hose. So, apparently, does the gopher.