Specialists provide tree recovery tips following Winter Storm Uri

Stephen O'Shea, Texas A&M Forest Service tfs-oshea.jpg
To remove or not to remove? That is the question many Texans are trying to answer about their trees damaged by Winter Storm Uri.
Anything green means a chance of recovery

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 Texans wondering what they should do.

This spring, Texas A&M Forest Service (TFS) joined forces with Neil Sperry, a Texas gardening and horticulture expert and author of books such as Neil Sperry's Lone Star Gardening, to send a unified message across the state to wait before removing trees. Gretchen Riley, TFS Urban and Community Forestry program leader, took it a step further asking Texans to wait until mid-July before cutting down leafless trees.

The good news is that the vast majority of trees late to leaf out have mostly, if not fully, recovered, experts said. Sickly or struggling trees are harder to come by, and time has lent clarity as to the state and survivability 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,” Sperry said, who has been studying Texas tree recovery since the storm.

The short answer

Now is the time for Texans to make a decision to remove or not remove trees.

According to Riley, if a 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, she said. And unfortunately, this applies across the board, even to palm trees.

“Anything green means that the tree has a chance for recovery. 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,” Riley added.

But before removing lifeless trees, homeowners are encouraged to seek the help of a professional or certified arborist.

Common scenarios

Few trees remain completely bare. The more common scenarios arborists and foresters are seeing statewide are trees with poor or patchy canopies. By mid-summer, and with all the rain received throughout the state, healthy trees should have a full canopy of leaves. The ones that don’t were affected by the freeze, experts said.

There are a few ways to determine if a tree is in good shape or could use a helping hand.

“Trees that have 50% or more of their normal canopy are likely to survive,” Sperry said, 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.”

Less-than-25-1-tfs.jpgIf more than 25% of branches are filled with leaves, there is still a chance for full recovery, according to experts. (Photo by Texas A&M Forest Service)

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

“Imagine a circle around all of your tree’s branches,” Riley said. “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.”

Twitter graphics.png

To monitor a tree’s progress, Riley recommends taking a photo of the tree’s canopy as soon as possible, remembering the angle from which it was taken. Then 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, she said.

Other complications

Many Texans are also 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,” Riley said.

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, she added. As the water inside the trunk and branches froze, it expanded. But with the 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, she said. The recent surge of summer heat has exacerbated those cracks, making them more visible.

“The good news is that trees have amazing, built-in mechanisms for recovering from trunk damage and frost cracks,” Riley said. “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. Exceptions include lacebark elms, sycamores and crape myrtles, Riley said. 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.

Oak-Tree copy-tfs.jpgThe recent surge in heat is making frost cracks from Winter Storm Uri more visible. (Photo by Texas A&M Forest Service)

Still, Sperry said homeowners should watch closely for oozing discharge and other signs of stress, such as browning foliage or expanding cracks, leading up to next spring.

Root shoots

A large number of trees and a variety of species are sprouting 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, Riley said.

“The strong healthy root system present from your previous tree will help your new tree grow at a faster rate than newly transplanted seedlings,” Riley said. “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.”

The old tree will still need to be removed, which will save the cost of grinding the stump, and buying and planting a new tree, which would likely grow at a slower rate than the root shoots. Crape myrtles, in particular, can grow back with astounding speed, Sperry said.

“You’re not going to lose a crape myrtle to cold. It might freeze to the ground, but it will come back,” Sperry said. “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-foot crape myrtle grow back in two to three years.”

Tree pruning and removal

When or how to remove a tree can be a difficult decision. Start by removing dead branches or by pruning back the dead ends of branches that experienced significant dieback. These branches are more likely to break off and injure property or people than the main body of the tree. Because tree removal can be a dangerous and difficult task, the TFS, Sperry and industry experts 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,” Sperry said. “They will have the tools, and they will have the knowledge and experience to do it safely.”

Tree care and tree replacement

Once trees have been pruned or removed, experts said it’s essential to maintain a watchful eye. The trees have been spoiled with an unusually wet spring and summer, but with August coming in hot and fast, Texas soils can dry quickly.

“They’ve been stressed, and they don’t need any more stress,” said TFS Staff Forester Courtney Blevins. “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."

If replacing a tree that's been removed, Sperry recommends not planting the new tree right where the old one existed, unless the stump has been ground out.

For more information, contact the Texas A&M Forest Service.

Source: is AgriLife TODAY, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.

 

Hide comments
account-default-image

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish