People come to the Hill Country for the trees, and one tree can add more than $10,000 to the value of a piece of property.
The continuing drought, though, has them all in jeopardy.
The bad news is some won’t survive, no matter what you do for them. The good news is most of the large, valuable trees will make it through...and you can improve their chances.
Robert Edmonson, an arborist with the Texas Forest Service, told an audience at the First United Methodist Church in Johnson City there are more big trees in the Hill Country now than there were a century ago.
“Our big trees, the ones we worry about most, have been through droughts before and survived, so most of them are even more likely to survive this one, even if it gets worse before it breaks,” he said.
The best chances go to upland trees, which are used to less water, and deciduous types, which lose their leaves in winter and already know how to conserve what water they have by dropping leaves. Some trees will even drop their big leaves and grow smaller ones, which lose less moisture through evaporation.
“In addition, trees in clay soils, rather than sand, have an advantage because clay holds water better. Those with a water supply — whether it’s an aquifer or your hose — will do better. Age is an advantage, too, because old trees have been through this before,” Edmonson explained.
How much to water a tree? A lot for mature trees, he said.
Edmonson said a mature tree wants about a half gallon of water a week for every square foot of ground shaded by the canopy.
He also said almost all of a tree’s roots are in the top three feet of soil, with the feeder roots in the top half of that, but they extend out from the trunk as much as twice the distance from the trunk to the drip line, much farther than most people realize.
He recommends concentrating water for mature trees near the drip line — the edge of the tree’s canopy of leaves.
For young trees and new plantings, “you should know where their roots are, because you planted them. If you put a tree with a two-foot root ball in the ground last year, water within two feet of the trunk, because that’s where the roots are.”
Edmonson also recommends finding ways to keep water in the ground where you put it.
“Build a low berm around the tree, just beyond its drip line, and fill the space under the canopy with mulch. Berm keeps the water from running off, while mulch keeps it from evaporating. Just don’t mulch right up to the trunk, which can promote disease.”
So the key question is, if my oak drops its leaves, is it dead?
“Maybe, maybe not,” Edmonson told the anxious group.
“Remember deciduous trees, like pecans and live oaks, drop their leaves this time of year anyway, so it may be natural. Evergreens that turn brown are in trouble.
“Don’t be too quick to give up on a tree, though. It may be dropping leaves as a defensive measure, and may come back green again in the spring if it gets water. Give it at least a year, maybe two, before you get out the chainsaw.”