Don’t cut down those ‘dead’ oak trees just yet
Three months after Winter Storm Uri blasted Texas with a week of freezing temperatures, many landowners are concerned the cold weather killed their oak trees.
Texas has a wide variety of native oak species, with many prized trees on private and public lands estimated to be hundreds or even thousands of years old. So, landowners were understandably alarmed when other species of trees budded out as normal while oaks remain bare-branched or sparsely leafed.
But Texas A&M Forest Service (TFS) experts caution Texans not to throw in the towel yet when it comes to the hardy oaks.
“I think most of the oaks are going to come through okay. If your tree is leafing out really late, it’s obviously stressed. But most trees die from a combination of stressors, not just one thing,” Courtney Blevins, a TFS forester in Fort Worth, said. “If your tree is dead, there’s no rush to take it down. That’s one big mistake people are making. They’re in a big hurry to take that thing down, thinking it’s dangerous to leave a dead tree standing, and it’s not.”
What likely happened instead is that the oak trees had already expended energy into producing new buds for this year’s growth, thanks to warmer-than-average temperatures throughout much of the winter.
When the artic weather arrived in late February, the liquid components of starches, sugar and water pulled from the roots to develop buds froze, effectively killing off new growth.
“That super freeze froze back a lot of those buds that were about to open up,” Blevins said. “Now, the trees that were preparing to bud out have to generate a whole new set of buds to leaf out, and that takes time.”
The dieback is not unusual and even expected during long, hard freezes. It just may have hit Texas’ oaks harder because they were already struggling, according to Gretchen Riley, TFS Urban and Community Forestry Program leader.
“It’s been a tough decade for trees. In 2011, we had unprecedented drought across the state, and we lost 500 million trees,” she said. “Those that we didn’t lose experienced pretty heavy stress. And in the past decade, we’ve seen a lot of tree mortality that really had its roots in that drought.”
Now, TFS biologists and arborists in Central Texas are seeing a drastic increase in caterpillars. As stressed trees are more susceptible to disease pathogens and insect damage, many are losing what vegetation they had to the hungry insects.
It’s tempting to try different fertilizers or pesticide sprays to help the trees recover, but TFS advises landowners that a “wait and see” approach is the better course of action right now.
Unless the tree has been diagnosed with a specific nutrient deficiency, fertilization may do more harm than good. Indiscriminate fertilization can lead to growth spurts, but the trees need to focus energy into repair and defense, Blevins said.
“[The trees] have been stressed, and they don’t need any more stress,” Blevins said. “So, I’m telling people, when we get into the heat of the summer—especially if we have abnormal heat, like we’re supposed to this year—one thing you might want to do is maybe give them supplemental watering once or twice.”
While trees without any leaves on them by mid-July are likely dead, other trees may take a full year to recover from the winter storm, Riley noted. If oaks look sparse or sickly this year, it’s okay to wait until next spring to see what develops before making any final decisions.
Many of the oldest trees have survived decades or centuries without human interference, so Riley recommends waiting as the best approach to saving stressed oaks.
“The best thing to do with mature trees is nothing,” she said. “Trees are very sensitive to change. And many of these mature trees may be a hundred years old. They’ve done really well without us. They’ve done their best to adapt to living around us, and most things that we would go in and do to them now are more stressful to them than helpful.”
Private pesticide applicator training
The Texas A&M AgriLife Extension Service in Brown County will conduct a private applicator training on Tuesday, June 1 in Brownwood.
The training will be at the Brown County Extension Office 605 Fisk Avenue. Anyone interested in attending this training should contact the Brown County Extension Office at 325-646-0386 and pre-register.
The training is specifically for those seeking a Texas Department of Agriculture private applicator license and is not a continuing education unit training.
The license is required to buy and apply restricted use/state limited use pesticides.
The Texas Department of Ag requires this training prior to being tested for a private application pesticide license.
Individual registration is $50 due upon arrival.
The training on June 1st will begin at 8:30am with registration and end at noon.
Wednesday, June 2 is the date of the next Lunch-N-Learn program. This will be the third program in a series being conducted by the Texas A&M AgriLife Extension Service. It will be held at the Brown County Extension Office located at 605 Fisk Avenue, in Brownwood from 12 noon – 1pm.
The June 2 program will focus on fresh homemade salsa and will feature Courtney Parrott, Brown County Family and Community Health Agent, program participants will be able to sample fresh homemade salsa’s complete with recipes. The Lunch-N-Learn series is 4 programs running April – July that focus on tomatoes, trees, and turf.
There will be a $10 registration fee payable at the door on June 2nd for those that have not already paid registration fee for the entire series. For more information contact the Brown County Extension Office at 325-646-0386.