What to do with Trees Recovering from Winter Storm Uri 
by: Stephen J. O’Shea

It has been almost six months since winter storm Uri blanketed Texas in a week-long freeze and, despite ample rain, many Texas trees are still showing signs of stress. Tufts of leaves give some a patchy, inverted look – while others are losing vast amounts of bark, or seemingly dying overnight – leaving many Texas home and land owners wondering what they should do.

Texas A&M Forest Service and Neil Sperry, the Texas gardening and horticulture expert, joined forces this past spring to send a unified message across the state: wait. More specifically, Gretchen Riley, the Urban and Community Forestry Program Leader at Texas A&M Forest Service, asked Texans to wait until mid-July before cutting down leafless trees.

The good news is that the vast majority of trees that were late to leaf out have mostly, if not fully, recovered. Sickly or struggling trees are harder to come by, and time has lent a level of clarity as to the state and likelihood of survival for most struggling trees.

“The waiting was important, because we’re just now beginning to differentiate between those trees that are obviously not going to survive; those that are wounded and we hope will survive; and those that are definitely going to survive, but are going to take a little while to come back,” said Sperry, who has been studying the recovery of Texas trees for the past several months.

Now the time has come for Texans to make a decision: to remove their trees, or not to remove their trees.

Struggling Trees 1

THE SHORT ANSWER 

According to Riley, if your tree is bare and hasn’t put out a single leaf by now, it is almost certainly dead. Waiting a few more weeks, or even months, won’t change that. And unfortunately, this applies across the board: even to palm trees.

“Anything green means that the tree has a chance for recovery,” said Riley. “But a single small frond should have grown and opened on palm trees by now. No green means it is dead and has already started rotting internally.”

If this is the case for any of your trees, it is probably time to consider how and when to remove your tree. The short answer: when convenient, and with the help of a professional or certified arborist.

THE LONG ANSWER 

By this point, few trees are still completely bare. The more common scenarios that arborists and foresters are seeing across the state are trees with poor or patchy canopies. By this point in the summer, and with all the rain we’ve been receiving, healthy trees should already have a full canopy of leaves. The ones that don’t were clearly affected by the freeze, as detailed in our article from May.

This isn’t to say they won’t be healthy and happy come next spring. And there are a few ways to determine if your tree is in good shape, or if it could use a helping hand.

“Trees that have 50% or more of their normal canopy are likely to survive,” said Sperry, referring to hardwoods and established trees. “But if it’s a 20% or 30% canopy over the whole tree, then that tree has suffered a bad hit, and it may not have enough to come back.”

It can be hard to remember what a full canopy looked like for a previously healthy tree, and so Gretchen Riley has come up with another method for determining a tree’s state.

“Imagine a circle around all of your tree’s branches,” said Riley. “Twenty-five percent or more of that circle should be filled in with leaves. If not, that tree is most likely going to die, and it is worth planning to remove it. If more than 25% of that circle is filled with leaves, there is still a chance for full recovery.”

One way you can monitor your tree’s progress is by taking a photo of your tree’s canopy as soon as possible. Keep that photo—remembering the angle you took it from—and then wait for next spring. Once the tree has fully leafed out, take another photo from that same spot, and compare the pictures for improvements. If there is more foliage next spring, that means the tree is in recovery.

Treees

OTHER COMPLICATIONS 

Patchy foliage isn’t the only mark of a stressed or struggling tree. Many Texas landowners are finding deep, wide cracks in the trunks of their oak trees. According to Riley, these are an exaggerated manifestation of the more typical frost cracks or “radial shakes.”

“Frost cracks are caused by a tree’s inability to endure expansion and contraction of the bark and wood that results from the freezing of water inside of the tree,” said Riley.

Water expands when it freezes, and since trees are more than 50% water, trees that had started coming out of dormancy leading up to winter storm Uri were particularly vulnerable to frost cracks. As the water inside their trunk and branches froze, it expanded. But with their outer-layer and bark also frozen, the outside of the tree wasn’t able to expand with the inside – leading to ruptures in the trunk and bark.

Many of these cracks were only partially visible, if not invisible, following the winter storm. The recent surge of summer heat, however, has exacerbated those cracks, making them more visible in some trees.

“The good news is that trees have amazing, built-in mechanisms for recovering from trunk damage and frost cracks,” said Riley. “So trees with one or two cracks should be able to seal themselves with relative ease.”

On the flip side, bark is still essential for protection against pests and diseases. Trees with multiple cracks or lots of exposed wood are unlikely to recover, and trees with few but deep cracks should be monitored closely.

The few exceptions are lacebark elms, sycamores and crape myrtles. These are more likely to survive since, in most cases, the damage appears to be a shredding of the outermost layer of bark, sparing the wood itself. However, you should still watch closely for oozing discharge and other signs of stress, such as browning foliage or expanding cracks, leading up to next spring.

Tree Bark Comparison

ROOT SHOOTS 

Surprisingly, a large number of trees, and a variety of species, are sprouting up shoots from the base of their trunks and root systems. While this might seem like a desperate attempt from the tree to stay alive, it’s actually a great way for landowners to grow and nurture a tree from a tiny sapling back to a fully grown adult. And it can mature much quicker than usual.

“The strong healthy root system present from your previous tree will help your new tree grow at a faster rate than newly transplanted seedlings,” said Riley. “This fall, select the best five or so sprouts and prune away the rest.  Let those five grow next year, and then select the most vigorous of those to be your new tree.”

You will still have to remove the old tree, but this method should save you the cost of grinding its stump, as well as buying and planting a new tree: which would likely grow at a slower rate than your root shoots, anyway. Crape myrtles, in particular, can grow back with astounding speed.

“You’re not going to lose a crape myrtle to cold. It might freeze to the ground, but it will come back,” said Sperry. “And if you have it trained as a tree—as is usually done with Tuscarora, Muskogee or Natchez crape myrtles—you can have a 20-ft crape myrtle grow back in two to three years.”

TREE PRUNING AND REMOVAL 

There are few decisions more difficult than when or how to remove a tree from your property. Trees have immense sentimental and monetary value. But their worth is rarely more than your roof, your house, or your life.

You can start by removing dead branches, or by pruning back the dead ends of branches on trees that experienced significant dieback. These branches are more likely to break off and injure property or people than the main body of the tree. It is still a dangerous and difficult task, though, and Texas A&M Forest Service—along with Neil Sperry and countless other industry experts—highly recommend enlisting the services of an I.S.A. certified arborist.

“When having major tree work done, you really need a specialist who knows how to do it safely,” said Sperry. “They will have the tools, and they will have the knowledge and experience to do it safely.”

Lacebark Elms

TREE CARE AND TREE REPLACEMENT 

Once your trees have been pruned or removed, it’s essential to maintain a watchful eye. Our trees have been spoiled with an unusually wet spring and summer, but with August coming in hot and fast, Texas soils are bound to dry up quickly – and our trees don’t need anything that might put them over the edge.

“They’ve been stressed, and they don’t need any more stress,” said Courtney Blevins, a Staff Forester and subject matter expert at Texas A&M Forest Service. “So when we get into the heat of August, one thing you might want to do is give them deep, supplemental watering once or twice.”

Meanwhile, if you’re planning on replacing a tree that you’ve had removed, Sperry recommends that you don’t put the new tree right where you had the old one, unless you have the stump ground out when a professional comes to remove the dead tree.

MOVING FORWARD 

Winter Storm Uri was an unprecedented experience for much of Texas. Temperatures fell well below freezing, plaguing the state for almost an entire week – and it hit right after a heat wave triggered many of our state’s trees into leafing out early.

So don’t overthink which tree to plant next, or whether you should remove a tree before its time. Simply remove the ones that are dead or dying, take care of the trees that are still living as best you can, and look forward to next spring, when they will hopefully come back in full. 

Contact:

Courtney Blevins, Staff Forester, Texas A&M Forest Service, cblevins@tfs.tamu.edu, (817) 531-3119

Gretchen Riley, Urban and Community Forestry Program Leader, Texas A&M Forest Service, griley@tfs.tamu.edu, (979) 458-6650

Stephen O’Shea, Communications Specialist, Texas A&M Forest Service, stephen.oshea@tfs.tamu.edu, (979) 458-6649

Help Mino ride for trees! Support Mino and Team Texas ISA in the Tour de Trees 2021!

I would sincerely appreciate your donation and am excited to be the captain of the Texas Team.  I registered for the 3 day ride which will take me from Aurora to Fort Collins, approximately 187 miles.  Colorado is my second home which is one of the reasons I signed up for the ride.  This will be a very challenging ride both physically and mentally but will also be very rewarding.  I’ve heard nothing but good thing about this ride and look forward to meeting new people and making new friends.  Below is the link to my fundraising page.  If you have any questions, or need any additional information, please feel free to contact me.  herminio.griego@sanantonio.gov

https://tour-des-trees-2021.blackbaud-sites.com/fundraising/minos-fundraising-page

Mark your calendar now for the biggest and best Texas Tree Conference yet!
Registration is opening soon!
Waco Convention Center
September 29 – October 1, 2021

Click here for more information

 

Basic knowledge of proper tree care helps individual tree owners understand the quality of care necessary for the health of their trees.  ISA provides detailed educational brochures to help tree owners understand best management practices and to promote a greater awareness of the benefits that trees provide in our communities. The brochures offer guidance for management throughout the life of a tree, from tree selection and planting to mature tree care and risk assessment.

 

View the recorded webinar with Dr. Appel and a panel of experts: Texas Trees and the Blizzard of ‘21: What’s Next? Here (free for members)

TFS NEWSROOM: OAK TREES ARE STILL RECOVERING FROM THE WINTER STORM
Connect | Oak Trees are Still Recovering from the Winter Storm TFS (tamu.edu)

Driving across Texas has been an interesting occupation for foresters and arborists these past few weeks. Many trees appear as healthy and vibrant as they have ever been, but littered in among the growing green are an equal – and seemingly arbitrary – population of barren oak trees.

This bizarre phenomenon has intrigued professionals across the state – especially since oak trees, and particularly live oak trees, are known to be an incredibly resilient species. Now, months after Winter Storm Uri swept across Texas in mid-February, many of them still aren’t leafing out. Standing in contrast to their vibrant and vivacious brethren, they look dead.

Oak Trees 3

 

Courtney Blevins has spent almost 40 years with Texas A&M Forest Service, and he can’t recall any past freeze leaving so many oaks looking bare this late into the spring.

“I’ve been telling people my whole career that the single toughest species we have up here is live oak,” said Blevins, a forester out of Fort Worth. “And yet, it’s the live oaks that seem to be most stressed from this freeze. I’m shocked by that.”

Blevins isn’t the only one. Neil Sperry, a Texas gardening and horticulture expert known across the state, has been stunned by the variability, and the scope, of damage left in the wake of that 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.”

WHAT EXPERTS ARE SAYING

Blevins and Sperry have spent the past few months responding to residents and landowners who are concerned about the health and condition of their trees. But as the weeks ticked past—and oak trees across the state still didn’t leaf out—Sperry decided to pull together a blue-ribbon panel of certified arborists, foresters, horticulturists, Extension specialists, nursery leaders and garden communicators to send out a unified message. Their advice to landowners who are wondering what they should do, and whether they should cut down their valuable trees, is a simple one: just wait.

“If your tree is dead, there’s no rush to take it down,” said Blevins. “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.”

Trees can stand firm for years after they have died. And while nobody wants a dead tree in their yard for long, landowners who are eager to replace their dead or dormant trees should note that spring isn’t the best time of year to plant trees in Texas, anyway. Instead, Texans should plant trees in the fall or early winter, when the roots are able to grow and further establish the tree.

But Blevins and Sperry are more concerned about landowners cutting down trees that could have recovered, if just given the time.

“I think most of the oaks are going to come through okay,” said Blevins. “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.”

Gretchen Photo 1

 

WHAT HAPPENED

With a prolonged, deep freeze like the one brought on by Uri, experts expected some kind of response from trees – primarily fine-twig and branch dieback. The outermost branches and stems of even the most established trees lack insulation, and are at risk of freezing 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, especially given past conditions.

“It’s been a tough decade for trees,” said Gretchen Riley, the Urban and Community Forestry Program Leader at Texas A&M Forest Service. “In 2011 we had unprecedented drought across the state, and we lost 500 million trees. Those that we didn’t lose, they 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.”

Riley attributes the potential mortality of mature oak trees to that drought and other, pre-existing conditions, but she attributes the overall delay in leafing out to a natural, physiological process that was interrupted by the freeze.

Every February in Texas, trees begin the process of pulling nutrients from their roots up into their branches and the finer 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.

It’s also worth noting that the week before the freeze, temperatures reached as high as 80° F across the state. Warm temperatures like that often cue trees to begin the process of budding out, and in Texas late-February is as common a time as any for trees to start leafing out.

“That super freeze froze back a lot of those 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 to leaf out, and that takes time.”

This theory would best explain the variability of the impact that Texans are seeing on their trees, since there doesn’t appear to be much of a correlation between which species of oak have been hit the hardest, or why urban trees are experiencing equal delays in leafing out.

It would also help explain why some of the trees that were late to begin leafing out are still struggling. With the last of their energy reserves being put toward re-producing buds and leafing out, they have little energy left to put toward defense. In Central Texas, in particular, Texas A&M Forest Service biologists are seeing a significant population of caterpillars. With the trees being more susceptible to disease pathogens and insects, many are losing their leaves to insects as they’re actively trying to leaf out.

Neil Photo 1

 

 

WHAT YOU SHOULD DO

While this helps explain what is happening, 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.

“They’ve been stressed, and they don’t need any more stress,” said Blevins. “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.”

Other than the occasional watering—and you don’t want to overwater your trees, lest the roots be flooded with water and lack the oxygen they need to breathe—Blevins recommends patience. Even fertilization should be avoided unless the tree is experiencing a specific nutrient deficiency. Fertilization leads to growth spurts – and when a tree is putting its energy into growth, any energy that could be applied to defense goes down.

Insecticide and fungicide are tempting treatments as well – since stressed trees are more susceptible to disease and insect infestation – but again, Blevins and Riley counsel patience. There’s no need for “preventative” treatments, and insect infestations and diseases should be treated on a case-by-case basis.

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.

“The best thing to do with mature trees is nothing,” said Riley. “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.”

Oak Tree 2

 

MOVING FORWARD

With the list of stressors piling up this year, it’s likely that many of the trees which were late to leaf out will continue to appear splotchy, sickly, or partially bare. In Riley’s experience, that is not unusual in itself, and many trees should be okay if they’re given the opportunity to leaf out normally next spring.

That being said, the trees that continue to appear bare may not come back.

“If by mid-July they have zero leaves on them, that tree’s dead,” said Riley. “If they have a small, poor showing of leaves, you might wait until next year to make that call. It could improve.”

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.”

If you’re concerned that the trees on your property are suffering from more than just stress, visit our page After the Storm. For more specific concerns, contact a certified arborist. You can find professionals in your area through the Texas A&M Forest Service’s My Land Management Connector app, or at treesaregood.org/findanarborist.

 

Texas A&M Forest Service will continue to monitor and study the impact of winter storm Uri on our state’s trees. For more information, and to stay up-to-date with our findings, make sure and follow us on social media at @TexasForestService, and on twitter at @TxForestService.

Contact:

Courtney Blevins, Staff Forester, Texas A&M Forest Service, cblevins@tfs.tamu.edu, (817) 531-3119

Gretchen Riley, Urban and Community Forestry Program Leader, Texas A&M Forest Service, griley@tfs.tamu.edu, (979) 458-6650

Stephen O’Shea, Communications Specialist, Texas A&M Forest Service, stephen.oshea@tfs.tamu.edu, (979) 458-6649

 

Free For ISAT Members – 1.5 Hours – 1 ISA CEU ($45)

If you are an ISAT member, you were invited to watch Dr. David Appel from Texas A&M University and a panel of long-time arborists from around Texas discuss the impact of the deep freeze of 2021 on Texas trees and plants. The panel discussed the science of freeze damage and shared their experiences with similar storms in the 1970’s and 1980’s. This webinar was recorded and now you can listen and learn about how to best care for trees after the big freeze of ’21. You must be a Texas Chapter ISA member to view this free webinar. (ISAT members can contact Misti Perez at misti@isatexas.com for the Discount Code for free viewing)

Non-members: When you register for this webinar and pay your $45, you will automatically receive a discounted, one-year Texas Chapter ISA membership.

Click here to watch the Texas Trees and the Blizzard of ’21 recorded webinar

Recent weather events have taken a toll on Texas Trees.

 

College Station, Texas (February 2021) – Right now, severe ice storms are crippling communities across Texas where the first order of business is clearing roads and restoring power. The Texas Chapter of the International Society of Arboriculture (ISAT) also reminds homeowners that what’s fallen to the ground after an ice event is only part of the overall danger when working around damaged and ice-covered trees.

According to the Sperry-Piltz Ice Accumulation (SPIA) Index, a tool used to predict potential damage in an ice storm, a quarter to a half inch of ice combined with wind gusts of 25 to 35 miles per hour can cause excessive damage to tree limbs. This exposes people to an increased risk because potential hazards are not always obvious to the untrained eye.

A.J. Thibodeaux, ISAT Chapter President and ISA Certified Arborist® states that the weight of the ice puts major stress on a tree, which might require restoration pruning or the addition of supplemental support such as cables or braces.

Tips on Hiring a Tree Service:

  • Dangerous work such as pruning or removing trees—especially large trees—should be left to professionals who are trained in the art and science of care, maintenance and safety.
  • Be sure to ask for proof of insurance before hiring a tree service for the job. A reputable company will have personal and property damage insurance and coverage for worker’s compensation.
  • Don’t hire someone asking for your business door-to-door and offering reduced rates for tree work. Most reputable companies will not solicit work this way.
  • Never allow a tree professional to ‘top’ your trees. Topping trees does more harm than good. It increases the tree’s recovery time and makes the tree more dangerous.
  • Find a qualified ISA Certified Arborist in your area by visiting ISA’s consumer website, www.treesaregood.org.

Here are some links that can help you care for your trees:

From the Texas A&M Forest Service

Can My Tree Be Saved?
Tree First Aid
Chainsaw Safety
Hire an Arborist

Click here to see how you can manage tree hazards and risk…

January 13, 2021, Noon to 1:00 PM
1 ISA CEU
Test and improve your Texas tree diagnosis skills!
Register today for both the free video quiz and the live webinar review session to earn two CEUs and become a better tree disease diagnostician.

Click here for more information.

The ISAT Annual Member Meeting Goes Virtual

September 25, 2020 from 10:00 to 11:00 AM

Join the Texas Chapter ISA Board of Directors for the 2020 Annual Members Meeting
This year, instead of the usual meeting at the annual Texas Tree Conference, the annual business meeting will be held online. The meeting will last about an hour and will include:
  • The Year in Review
  • Recognition of this past years Officers and Directors
  • Installation of the new ISAT Officers and Directors
  • Awards
  • Questions and comments from the membership
See you online!

You can register here

We’ve added a new listing of webinars and webcasts to keep you up to date on the latest arboricultural info and CEU opportunities. Click here or on the events menu to learn more.