Tag red oaks

Are Trees Still Showing Signs of Freeze Damage? [May 2022 UPDATE]

by Texas Tree Surgeons Extreme Weather, Resources, Tree Health Care

Unfortunately for trees in North Texas, the effects of the February 2021 winter storm, often called “Winter Storm Uri” in the media, are still with us. The historically-low temperatures and winter precipitation in 2021 and the winter weather in February 2022 had a devastating impact on the health of trees and other vegetation and  recovery from those extreme conditions will take time. Common landscape trees in the DFW area, such as ash, live oaks, red oaks, wax myrtles, chinaberries, and Chinese tallow trees were some of the worst damaged by the freezing conditions and so the damage can still be seen in many parts of our community.

Different species and types of trees responded differently to the low temperatures.
Visit our previous posts for specific info:

My Tree Leafed Out in Spring 2022 but is Now Turning Brown. Is That Freeze Damage?

Due to the unprecedented nature of the winter weather in 2021 and 2022, it has been difficult to predict exactly how trees will respond and the nature and timing of any freeze-related decline.

  • Some species have seemed to bounce back from freeze damage only to show browning and die back after two or more growing seasons.

    • Red oaks and Japanese maples have been observed to leaf out in the spring as normal, only to start browning a few weeks later.

    • Unfortunately, once a tree’s canopy has completely browned or died, the tree may not be salvageable.

  • If a tree has partial browning or only some dead canopy:

    • Prune out the dead or dying sections

    • Follow good watering practices

    • Use soil amendments focused on increasing available nutrients

      • High nitrogen fertilizer is NOT recommended, as this can stimulate the tree to use up energy reserves to push new growth rather than increase overall health

A tree exhibiting severe freeze-thaw cracks. Even less drastic cracking can reduce a tree’s defenses against pests.

Should I Be Worried About Cracks in the Bark of My Trees?

Freeze-thaw cracks occur when rapid temperature swings cause the wood of a tree to swell and contract faster than normal. These cracks vary in size and severity. When the water inside a tree freezes, it can damage the tree’s vascular system, which moves nutrients throughout the entire tree. Widespread damage to the vascular system can lead to tree death.

Trees with freeze-thaw cracks need special care to encourage vascular system growth and nutrient availability.

  • Proper watering is essential.

  • Soil amendments and low nitrogen fertilizers can make additional nutrients readily accessible to the tree’s roots.

    • Fertilizing stressed and damaged trees must be done with care.

    • High nitrogen growth stimulators should be avoided.

  • Preventive insect treatment is recommended.

    • Cracks or other wounds in the bark are entry points for borer beetles and other pests.

    • Over time, the tree will be able to seal off (“compartmentalize”) the damaged sections, but this can be a slow process.

Why Does My Tree Have Large Dead Branches?

In cases where only parts of a tree were subject to severe frost damage, the main trunk may be free of freeze-thaw cracks or other issues while some large or small sections of the tree show browning and dieback. With rapid temperature swings and violent winter weather, a tree’s specific location and surroundings (such as nearby structures or other trees) can have a great impact on how the tree is affected. Because of this, trees of the same species on the same block may have shown wildly different responses to freezing weather. No matter the extent, it is best to remove dead and dying sections of the canopy and bolster the tree’s health with water and nutrients to give it the best chance to compartmentalize the dead and decayed sections and return to health.

At Texas Tree Surgeons, we love trees and we love our community! Recent extreme weather events present new challenges to our urban forest and it will likely be a few years before we have seen the full effects. Trees, by their nature, respond slowly to environmental changes and, if not properly cared for, can slide into a cycle of decline following storm damage or other severe weather. As we move into the heat of the summer our current drought conditions can worsen and accelerate tree decline and dieback. Now is the time to have one of our arborists evaluate your trees for their current needs and prescribe a health care plan to increase soil nutrient levels and manage insect activity. Contact us today!

Will My Trees Survive Freezing Temps and Winter Weather?

by Texas Tree Surgeons Extreme Weather, Resources

The effects of the historic freezing temperatures in February 2021 are widespread. After the ice thawed and the snow melted, many people were left with frost-damaged or dead landscaping. While much of the damage from the rapidly-changing temperatures is obvious, trees and plants have also suffered internal damage, and will likely show signs for years to come.

Will the freezing temperatures and winter weather kill my trees?

Unfortunately, we can already see the signs of frost-killed plants: leaves and other plant tissue that appears wet, soft, brown/black, or dried up. This type of damage is prevalent in succulents, pittosporum, loropetalum, geraniums, and related plants. Palms will likely also suffer extensive frost damage, but it is best to wait until the summer to see if they put out new growth. 

Evergreens and more frost-resistant trees and shrubs should fare better. Common examples of this group of plants are yaupon hollies, wax myrtles, and crape myrtles. These species may brown in sections, but ultimately survive. Even if they survive, some of the brown sections will never recover. It is best to wait until summer for new growth to see the extent of the damage. 

Trees with thinner bark, such as fruit trees and Japanese maples, may leaf out in the spring and appear unharmed. Damage to the inner layers of the tree, however, can prevent proper movement of water and nutrients in the tree’s vascular system and can lead to stress symptoms in the summer, appearing as a sudden browning and wilting of the leaves. 

Larger native trees such as red oak and pecan may show dieback or brown sections, but should recover if cared for properly. Live oaks may show browning, but should recover and put out new leaves in spring.

Frost Cracks

Frost cracks are caused not by surface frost, but by fluctuating temperatures, and are most-often seen on the southern sides of trees, which get more direct sunlight. On a cold but sunny day, the sun warms the exposed areas of the tree, causing expansion. When temperatures drop rapidly at night, the bark cools and shrinks faster than the tissue underneath. As the bark shrinks, it splits vertically over areas where the underlying wood is still expanded. Splitting and cracking is most common in areas where there are wounds or other damage that has weakened the bark. Young trees and trees with thin bark are especially susceptible. Frost cracks are rarely fatal and will heal over time, but can be entryways for disease and insects. Stressed trees exhibiting cracks should be given special attention and should be properly fertilized and cared-for to help protect against diseases and insect activity.

CAN I DO ANYTHING TO HELP MY TREES RECOVER FROM THE FREEZING WEATHER?

 For freeze-damaged plants, it is important to provide proper care in the short and long term. 

 WHAT YOU SHOULD DO NOW: WAIT!

  • Watch for signs of damage.
    • Browning and widespread leaf drop will be common.
    • Wait until spring or summer before deciding if a plant is salvageable.
  • Water correctly.
    • Once the ground has thawed out, and temperatures are consistently above freezing, do a deep soak watering for the roots of trees.
      • Use a hose, not sprinklers.
    • Watering can help a tree with damaged leaves to take up nutrients. 

WHAT YOU SHOULD DO IN THE SPRING

  • Have frost-damaged trees evaluated by an local ISA Certified Arborist.
    • Every tree species will react differently to the freeze.
    • Factors like location, soil conditions, and even the movement of the storm front will affect the trees’ ability to survive.

WHAT YOU SHOULD DO OVER THE NEXT FIVE TO SEVEN YEARS

  • Fertilization and proper watering will be key to freeze-damaged trees.
    • Nutrient-rich soil with beneficial bacteria and fungi can speed a tree’s recovery.
  • Do not use herbicides around affected plants.
    • Never use a “weed and feed” product near your trees.
  • Continue proper maintenance trimming and care.
    • Remove dead wood and loose bark, thin for light and air.

At Texas Tree Surgeons, we love trees and we love our community! The freezing weather in February 2021 caused damage not just to North Texas’s infrastructure, leaving many without power, water, and shelter, but also to our urban forest. Once the needs of our residents have been met, it’s a good time to think about how best to care for our frost-damaged trees and shrubs. We are here to help you evaluate the damage to your landscaping and make an informed decision about how to proceed. If your trees and shrubs don’t leaf out in the spring, or you have any other questions, let us know! We have a team of ISA Certified Arborists ready to help in any way we can!

Free Trees for Dallas Tornado Recovery!

by Texas Tree Surgeons Events

In October 2019, Dallas was hit with a devastating tornado. As part of ongoing recovery efforts, the Texas Trees Foundation is partnering with the Arbor Day Foundation and International Paper to give away 500 free trees to Dallas residents who were affected by last year’s storms.

Registration is open and continues until all trees have been allotted. The trees will be available for pick-up Saturday, October 31st.

This round, the available species are:

All of these are great Texas trees, but if you wonder which one might be best for your yard, get in touch with your arborist. We are happy to make a recommendation!

For more information about the tree giveaway and to register, visit the Texas Trees Foundation site.

At Texas Tree Surgeons, we love trees and we love our customers, and we are excited about these local programs to encourage tree planting! If you have any questions about the best way to plant a tree, or any other tree questions, let us know!

The Tornado Took All the Leaves Off My Tree; What Can I Do About It?

by Texas Tree Surgeons Extreme Weather, Resources

After a devastating weather event like the tornadoes on October 20, 2019, the damage can be hard to assess, let alone start to repair. While damage to homes and other structures is of utmost importance to the community, addressing the damage to our urban forest, and determining what can be saved, is a key component of recovering after destruction.

Cleaning up downed trees is the first priority in an emergency situation. Fallen trees can prevent first responders and repair crews from accessing damaged utility lines and dangerous structures. Once the trees on the ground have been addressed, however, we must think about those left standing. After a high-wind event like a tornado, the trees left standing often have severe limb breakage and defoliation, or loss of leaves. Both of these issues have short- and long-term consequences, that must be understood.

Tree Safety Is Key

As soon as possible after a storm, owners of damaged trees should take a few steps to ensure there is no further damage to people or property:

  • Clear the area around any damaged trees of vehicles and valuables and take steps to prevent access to the area.
    • If possible, cordon off the entire dripline area (from the trunk to the tips of the branches).
    • If there is a tree that could fall on your home, consider staying out of that part of the house until the tree can be assessed.
  • Once the area has been secured, contact a certified arborist to assess the damage to your trees.
  • Trees that are stable, but have lost a great amount of the canopy will probably need fertilization or other plant health care measures to recover.

Will My Trees Survive Tornado Damage?

Ultimately, the prognosis for a storm-damaged tree depends on several factors, including the species, location, soil condition, and underlying health of the tree. Based on our experience, however, certain North Texas trees should fare better than others.

  • Live Oaks, Cedar Elms, Pecans, Bur Oaks – Uncertain/Wait and See

    • While these species are resilient, we are assessing them on a case-by-case basis.
    • If the tree is stable, we recommend waiting until the spring to see if new growth appears.

  • Red Oaks, Maples – High Risk for Sun Damage

    • Both types of trees are susceptible to sunburn, which dries out the bark, causing it to peel off,  and exposing the sapwood underneath to damage.
    • Even if the tree is stable, the risk of stress and dieback from the winter sun is great.
    • Maples and red oaks that have lost their leaves have little protection from sun exposure.

  • Crape Myrtles – High Chance of Survival

    • As long as the crape myrtles remained in the ground, they should survive.
    • Damage to limbs and safety pruning may alter the shape of the tree, but should not cause any major issues.
    • If increased insect activity is observed, consider using insecticidal soap in the winter or pesticides in the spring.

  • Mulberries – Uncertain/Wait and See

    • Mulberries are fairly hardy, and may survive, but may suffer from dangerous instability.
    • Once tree is stabilized, wait to reassess during the next growing season.

  • Hackberries – Uncertain

    • Have the root area examined by a certified arborist for signs of root rot or kretzschmaria.
    • Even if the tree appears undamaged, the hackberry’s tendency to develop root instability issues may make it a fall risk in the future.

  • Magnolias – Unlikely to Survive

    • Extensive defoliation will likely stress the tree past the point of survival, and prevent recovery from any damage.
      • As evergreens, magnolias depend on their leaves year-round.

  • Ornamentals – Likely to Survive/May Want to Replace

    • Smaller trees and ornamentals seem to fare better in high winds, as they are able to flex with the pressure.
      • One risk to smaller trees is being damaged by falling debris from larger trees or structures. If there is no physical damage, the tree is probably stable.
    • Many smaller ornamentals are understory trees, used to shade from larger species.
      • As with red oaks, risk of subsequent damage from sun exposure is high.
    • Even if the tree survives, it may not be as well-suited for its space after the damage, and owners may prefer to replace it.
      • Defoliation or wind damage may have irreparably altered the shape.

What Should I Do Now?

Whatever kind of tree you have, and however it has been damaged, contact a certified arborist to determine the best steps to take. We highly recommend fertilization for all trees impacted by storms, especially in our urban soils. If your trees are going to recover, they will need all the nutrients they can get. If your landscaping has been disturbed by the tornado, now might be a good time to adjust your mulching practices to help enrich the soil going forward. If you need guidance, we are always here to help.

At Texas Tree Surgeons, we love trees and we love our customers. We are shocked and saddened to see the widespread damage and devastation after the recent tornadoes, and our hearts go out to all those who have lost their homes. So much of our beautiful urban forest seems to have been uprooted or destroyed, and we want to do what we can to preserve what remains. We hope this overview has been helpful, and we are always available to come out to assess your specific trees for damage, stability issues, health issues, or to give you our recommendations for post-storm care. Don’t hesitate to contact us with any questions you may have.

Free North Texas Trees for 2019!

by Texas Tree Surgeons Events

Just like last year, the City of Dallas is giving homeowners free trees as part of its Branch Out Dallas program!

Registration starts September 1st, and continues until September 30th. The trees will be available for pick-up November 2nd.

This round, the available species are:

All of these are great Texas trees, but if you wonder which one might be best for your yard, get in touch with your arborist. We are happy to make a recommendation!

For more information about the tree giveaway and to register, visit the Branch Out Dallas site.

If you are not a Dallas resident, you can request a free tree through a partnership of Oncor and the Arbor Day Foundation. Trees can be mailed or can be delivered, as available. Plantings will begin this fall.

Visit the Energy-Saving Trees site to see what trees are available in your area!

After the severe storm damage we have seen this year, it is time to start renewing our urban forest. Fall and winter are the best seasons to plant trees, so start the process now!

At Texas Tree Surgeons, we love trees and we love our customers, and we are excited about these local programs to encourage tree planting! If you have any questions about the best way to plant a tree, or any other tree questions, let us know!

What is Oak Wilt?

by Texas Tree Surgeons Resources, Tree Health Care

What is Oak Wilt?

At Texas Tree Surgeons, we love trees and we love our customers, and we have created a series of articles covering tree basics. If you have a specific tree question, let us know!

Oak wilt, and the precautions that need to be taken to help prevent the spread of this fungal disease, may be the most often talked-about aspect of tree health care in Texas. Throughout the state, tree owners and communities are challenged by the potential devastation to all species of oak tree. In some areas, there are ordinances in place that restrict oak trimming in order to prevent the spread of the disease. Other areas have no formal regulation, and this can lead to a lack of awareness and a potential for widespread infection.

While oak wilt is a serious threat to our North Texas urban forest, there are simple steps that everyone can take to lessen its impact.

What kind of Disease is oak wilt?

Oak wilt is an infectious disease caused by a fungus (Bretziella fagacearum*). All oaks (genus Quercus) are susceptible to oak wilt, but different species may react differently to the fungus. Oak wilt is a vascular disease, and infects the whole tree, even if only one part is symptomatic. As the fungus spread through the tree, it blocks the transmission of nutrients to the canopy, causing the characteristic “wilt,” or dieback.

In live oaks, infected leaves often show yellow-brown veins, even while still on the tree. In red oaks, leaves may simply wilt and brown. This process can lead to an autumn-like coloration during the summer. Additionally, fungal mats may form underneath the bark of red oaks, leading to cracking, peeling bark and a rotting smell.

While visual inspection is a strong indicator of the presence of the oak wilt fungus, laboratory confirmation may be required. The Texas Plant Disease Diagnostic Laboratory offers testing for oak wilt and many other diseases. For more information on how to submit a sample, see this post or contact your arborist.

Live oak leaves showing the venal necrosis characteristic of oak wilt

How do trees get oak wilt?

The most common ways for the oak wilt fungus to be transmitted are by insect activity and root grafting. Insects can infect a tree through any exposed wood (not covered by bark) or open wound (such as a pruning cut, broken limb, or where branches rub against each other). In situations with oaks planted in close proximity, the fungus can be transmitted from one tree to another via underground root grafting. As roots make contact with other roots, they grow together and share pathogens.

Different species of oak can contract and spread oak wilt by different methods.

RED OAKS

Red oaks (Texas, Shumard, blackjack, water) are extremely susceptible to infection through insect activity. Red oaks are often the primary mode by which oak wilt gains a foothold in a new area. The oak wilt fungus thrives in red oaks and creates visible fungal mats underneath the bark. These spore mats attract insects; sap beetles of the Nitidulidae family are the most common type. Beetles feed in the infected area and become covered with particles from the spore mats. Drawn to exposed wood on healthy trees, the beetles transfer the fungal spores, spreading the infection.

LIVE OAKS

In contrast to red oaks, live oaks are susceptible to oak wilt primarily through their root systems. In nature, live oaks often grow in groups, sometimes called motts. Underneath the mott, the root systems of the individual trees become interconnected. This grafting allows not only nutrients to be shared, but pathogens as well. Once a member of the mott has contracted the oak wilt fungus, the infection quickly spreads.

WHITE OAKS

White oaks (post, bur, chinkapin) are more resistant to oak wilt than other species, but are still at risk. Transmission generally occurs through spore transfer by insects, or by human activity.

Can you prevent Oak Wilt?

Oak wilt is an epidemic. Because of the concentration and susceptibility of oaks in Texas, especially red oaks, it can be difficult to isolate centers of infection and prevent further spread. The Texas A&M Forest Service and the Forest Health Protection branch of the U.S. Department of Agriculture have issued some guidelines to help prevent further tree death.

  • Remove and properly dispose of diseased red oaks immediately
    • Chip or bury all tree material
  • Do not transport unseasoned firewood
    • Firewood should be dry, splitting, and the bark should be peeling off
  • Do not store unseasoned oak firewood uncovered
    • Cover tightly with heavy, clear plastic and bury the edges to restrict insect access
  • Do not prune or otherwise wound oak trees from February 1 to July 1
    • The best time to trim is in the fall and winter
  • When infection is a risk, take proper precautions
    • Sterilize tools and paint cuts

If you have healthy oak trees in an area with infected trees, preventative treatment may be effective in slowing transmission. As oak wilt is a systemic, vascular disease, the most effective treatments consist of injecting the infected trees with a fungicidal chemical. The only currently recommended fungicide is Alamo®, a formulation of the fungicide propiconazole. The fungicide is administered through holes drilled in the root flare of the infected tree and should only be applied by Texas Department of Agriculture Licensed Applicators.

For large stands of oak trees, especially live oaks, trenching around the area and severing root connections can limit disease spread, as well.

A typical system for fungicidal injection; each green port is inserted into the living tissue of the tree.

Can you cure Oak Wilt?

There is no known cure for oak wilt. Reported home remedies or substances applied to the exterior of the tree have not be proven to have any remedial effect. If you have a tree that is infected with oak wilt, be sure to consult a Texas Oak Wilt Qualified arborist or your local Texas A&M Agrilife Extension agent to discuss treatment options.

Red oaks usually defoliate and die one to six months after becoming symptomatic. Live oaks may last up to a few years before total necrosis. White oaks show the most resistance to oak wilt and may survive several years after infection.

Fungicidal treatment may prolong the life of infected trees, but cannot eradicate the disease. However, systemic fungicides are most effective if a tree has not lost more than 30% of the crown. Contact a certified arborist to see if your tree may be a good candidate for treatment.

What areas have Oak Wilt?

In North Texas, there are many centers of infection. At Texas Tree Surgeons, we take oak wilt precautions throughout our service area. Still, there are a few neighborhoods in which we have seen particularly bad oak wilt activity:

  • Preston Hollow, Dallas
  • Lakewood, Dallas
  • Walnut Hill and Abrams, Dallas
  • Coit and Campbell, Richardson
  • President George Bush Turnpike and the Tollway, North Dallas
  • Park and US 75 in Plano
  • Highland Park
  • University Park

If you live in one of these areas, or suspect oak wilt activity in your neighborhood, contact your arborist to see what specific preventative steps are recommended for your trees.

Oak wilt is one of the greatest threats to trees in Texas. Education, awareness, and prevention are the best tools we have to protect our urban forest from devastation. If you want to learn more about oak wilt, visit TexasOakWilt.org.

At Texas Tree Surgeons, we love trees and we love our customers, and we believe that the more people learn about their trees, the better we can serve our community. We have several Oak Wilt Qualified arborists on staff; please let us know if you have any questions about oak wilt or any other tree question. We are always happy to help!

* – Until 2017, the oak wilt fungus was identified as Ceratocystis fagacearum.