More than two months following the record cold temperatures of Winter Storm Uri, Texans are noticing that some oak trees are still struggling to recover. This has left many of our state’s experts wondering why.
Even Neil Sperry, a Texas gardening and horticulture expert known across the country, has been stunned by the variability, and the scope, of damage left behind by the freeze. Followers of his Facebook page have submitted over 2,000 photos of struggling oak trees, including all varieties of species and from every single region of the state.
“I have been in this business professionally since 1970, and I’ve never seen anything like this,” said Sperry. “We think of oaks as permanent as concrete and steel, and for them to selectively be affected by this freeze is particularly odd.”
After spending weeks responding to residents and landowners who are concerned about the health and condition of their trees, Sperry decided to pull together a blue-ribbon panel of certified arborists, foresters, extension specialists, nursery leaders, horticulturists and garden communicators to send out a unified message. Their advice to those wondering what they should do, and whether they should cut down their valuable trees, is simple: just wait.
“If your tree is dead, there’s no rush to take it down,” said Courtney Blevins, a Fort Worth Forester with Texas A&M Forest Service. “That’s one big mistake people are making. They’re thinking it’s dangerous to leave a dead tree standing, and it’s not.”
There is no fixed date as to when you might know if your tree is going to survive or not, but Gretchen Riley—the Urban and Community Forestry Program Leader at Texas A&M Forest Service—is suggesting that, if your tree hasn’t produced a single leaf by July, it is most likely dead. For trees that are leafing out, but look scraggly or patchy in their canopy coverage, Riley and Blevins are more optimistic.
“I would wait until next spring to fully make a call on a tree that I care about,” said Riley. “Because they may struggle this year, but after a full year of normality, they may stabilize and come back healthy in the spring.”
With a prolonged deep freeze like the one brought on by Uri, Riley expected some kind of response from the trees – primarily fine-twig and branch dieback. The outermost branches and stems of even the most established trees lack insulation, and would die back in very low temperatures. This is a partial explanation as to why some trees have growth closer to their trunk and innermost branches, while the edges of their canopies remain bare – but it doesn’t explain why so many trees are leafing out late, or not at all.
One popular theory suggests that the trees that are struggling right now were likely stressed or struggling before the winter storm. Riley, for instance, attributes the potential mortality of mature oak trees to the 2011 drought and other pre-existing conditions, but she attributes the overall delay in leafing out to a more natural, physiological process that was interrupted by the freeze.
In mid-late February, Texas trees begin the process of pulling nutrients from their roots up into their branches and twigs. This combination of sugar, starches and water is then used to produce buds, which – over the course of a few weeks – become leaves, and supply the tree with food that can again be stored in the roots for the following winter. However, because there is a liquid component to this energy, it is susceptible to freeze damage. And once frozen, it cannot be repurposed.
“That super freeze froze back a lot of buds that were about to open up,” said Blevins. “Now, the trees that were preparing to bud out have to generate a whole new set of buds, and that takes time.”
While this helps explain the variability of the impact that Texans are seeing on their trees, most residents are more interested in how they can help their trees. Unfortunately, experts are saying there isn’t much you can do, and there is very little that you should do.
“When we get into the heat of the summer, especially if we have abnormal heat, one thing you might want to do is give them supplemental watering once or twice,” said Blevins.
Other than the occasional watering—and you don’t want to overwater your trees, and prevent them from getting the oxygen they need to breathe—Blevins recommends that you do nothing.
This information can be difficult for landowners and tree-lovers to absorb, since it is our tendency as stewards to want to do something. However, when it comes to our trees – especially our mature trees – often times, the more we do, the more harm we cause.
In any case, the consensus among professionals at Texas A&M Forest Service and across the state is simple and direct. Be patient.
“Just wait,” said Sperry. “These trees are coming back at their own pace. Some of them will be lost. But the important word continues to be ‘wait.’ Don’t start cutting those trees.”