Winter Tree Problems

The coldest months of the year can really test the hardiness of a tree. Weather conditions, wildlife, and salt runoff from hard surfaces cause some of the most common tree issues in winter, such as damage to bark and branches. In this article, we’ll explore the causes of these issues and explain how, with preparation and preventative care, much of the damage to trees in winter can be avoided.

What Are the Most Common Tree Problems in Winter?

Trees provide ecosystem services all winter long, but it’s also a harsh season that can create difficult conditions. The most common tree problems in winter include:

• Frost cracking

• Sunscald

• Late-season frost

• Snow and ice accumulation

• Wind and storms

• Damage from wildlife

• Salt 

• Winter drought

Many of these problems are caused by freezing temperatures, like the issues resulting from frost and ice, while others, like damage from wildlife and exposure to salt, result from the demands of the season on animals and humans. While these generally affect deciduous trees, whose winter adaptation is to go dormant, some evergreens might be affected by one or more of these issues as well. Planning ahead will help protect your trees from wintertime exposure.

Temperature Fluctuations

Frost cracking, sunscald, and late-season frost can each damage a tree in different ways, all due to the fluctuation between above- and below-freezing temperatures during the transitional periods of the year.

Some of these injuries are more common in young trees recently planted, without fully established root systems, or those species that are more marginally hardy to our area. Frost cracking, or bark splitting, occurs when moisture underneath the outer layer of bark thaws during the day from sunlight and rising temperatures, then freezes again at night, expanding as it quickly solidifies and cracks the bark. Bark is a tree’s natural protection, so broken outer bark exposes the sensitive inner layer of fresh, actively growing wood. Young trees that have been recently planted or with root disorders, and those with smooth, thin bark are most at risk for frost cracks, and they can be prepared for winter in late October by wrapping their trunks in burlap or another preventative tree wrap for insulation.

Similarly, sunscald can damage the bark of a young tree that hasn’t yet developed a robust layer of thick bark. When the sun shines brightly, or temperatures rise above freezing, a tree might warm up and begin to send nutrient-rich fluid up through the tree. If temperatures quickly fall again, that fluid will freeze and damage the tree’s tissue, resulting in dead material that looks like a burn. Wrapping young trees for winter moderates the tree’s inner temperature and can insulate against sharp swings in either direction.

Early spring-blooming trees can be damaged when late-season frost destroys buds that have started to emerge from warming temperatures. Flowering dogwood and eastern redbud are just a couple of the spring blossoms that can be affected by unexpected frost.

Snow, Ice, and Wind

Freezing temperatures, whether consistent or staggered, can cause problems for trees. Snow accumulation, freezing rain, ice, and winter winds can all cause problems for vulnerable or weak trees; however, with a heavy enough load even healthy trees can be damaged. One of the best ways to avoid a tree’s limbs breaking from snow, ice, or wind is to have it inspected and pruned regularly by a certified arborist who can identify weaknesses and potentially help a tree to withstand storms throughout the year.

Wildlife 

When vegetation retreats for the season, deer, rabbits, and other mammals have to find sources of food, and that often includes the green wood and thin bark of young trees (and sometimes the thick bark of mature trees). Deer can cause further damage to trees during the winter when they rub their antlers against trunks to scratch off velvet, and they rub their bodies against trees to leave their scent and mark their territory. Wrapping young tree trunks in burlap or another winter protective material or placing stakes or other physical barriers will keep animals from being able to access an otherwise vulnerable sapling. Generally, trees over five inches in diameter become less attractive to deer for rubbing.

Salt Exposure

Even though salt helps us navigate with ease in winter, all the extra salt can damage trees by running off into the soil, leading to dehydration or damage to the roots of trees along roads, sidewalks, and driveways. Using alternative de-icing materials like sand, gravel, and other non-sodium products, using salt minimally in targeted ways, or physically removing snow can help reduce the potential for stress on the trees. 

Ways to help a tree tolerate some winter salt exposure in neighborhood and urban environments include planting salt-tolerant species of trees (such as the American elm, bald cypress, white oak, and American sycamore, among others), using mulch in winter, and rinsing salt off and flushing the soil with water in early spring when the temperatures rise.

Winter Drought

Watering trees in winter is not frequently needed due to much lower evaporation and plant water needs, but some years winter can be just as dry as the heat of summer, with lower water vapor levels and low amounts of evaporation due to solid precipitation. Watering a tree in the winter can be tricky; choose a warm day above freezing to slowly water the roots from the trunk base out to the drip line (the furthest a tree’s crown extends). Watering early in the day can allow the water to seep down before freezing nighttime temperatures return, and good mulch cover over the roots helps insulate the ground and prevent moisture loss. When in doubt about watering, consult a certified arborist, or contact us at the Nashville Tree Conservation Corps for general guidance!

How Do You Tell Whether a Tree Is Dying in the Winter?

Noticing tree stress can be easier in the summer when the leaves are often a giveaway of dead branches or infection. However, winter provides an opportunity for arborists to inspect deciduous trees closely and trim them as necessary. Some obvious signs of a failing tree in winter include:

• Visibly broken or hanging branches

• A trunk and/or branches with decay, cracks, or without bark

• Evergreens with brown or yellowing leaves

• Unusual fungal or mushroom growth on or around the tree

A routine inspection by an arborist should catch structural problems before they become a hazard, but if you notice any of these signs between inspections, contact your certified professional to have the tree assessed for damage.

Fall and Winter Tree Planting in Nashville

While winter can create challenges for trees, it’s also a time of growth when trees build up their toughness for a long life in the elements. Trees can grow roots through the winter as long as the ground is not frozen, which is most of the winter in middle Tennessee. Fall and winter are the best times of the year to plant a tree, and the Nashville Tree Conservation Corps is here to make that happen! Our tree sale has a wide variety of species available, and you can even donate a tree to be planted! We also appreciate financial donations, which enable our work supporting Nashville’s canopy.

Volunteer with us, subscribe to our newsletter, or check out our Linktree to get involved and stay connected with NTCC!