Identifying Frost Crack On Your Trees

If you have ever heard what sounds like gunfire go off in the dead of winter and it isn't hunting season, it could be the sound of tree bark cracking. Frost crack is not a drug, but an occurrence distinct in thin barked trees, deciduous trees and trees that stand isolated rather than in groups or stands.

This isn't to say other types of trees don't develop frost crack. Trees that grow quickly and vigorously are more apt to develop frost cracks than very young or old trees. One can also find trees with frost crack that have some sort of weakness in the bark, which occurred to the tree earlier.

When and why does frost crack occur? Typically in late winter or early spring due to water building up within the tree's inner bark or xylem. As the wood expands and contracts with significantly fluctuating temperatures and the bark does not contract at the same rate as the inner phloem, cracking occurs.

Trees that are growing in poorly drained sites are more subject to frost cracking than are those growing in drier, better drained soils. Trees suddenly left exposed by felling are highly susceptible as well.

Frost cracks can be up to several feet long. You may not notice the cracks until spring and they are typically on the southwest side of the tree. Some cracks heals n the summer and then reopen again in the winter. If cracking and healing reoccurs the tree can develop frost ribs.


The wood beneath the frost crack is rarely damaged but the cracks can serve as sites of entry for wood decay organisms, including insects, fungi and bacteria. Timber damaged in this way is unsuitable for use in buildings, etc.


The sloughing or peeling of the bark is a normal process, especially in the spring when the tree begins to grow. The outer layers of the bark are dead tissue and therefore they cannot grow, the outer bark splitting in order for the tree to grow in circumference, increasing its diameter. The inner bark cambium and phloem tissues are living, and form a new protective layer of cells as the outer bark pulls apart. Most tree species try to seal the edges of wounds by forming a callus layer. The wound’s edges begin to form this callus during the first growing season after that crack appears and the callus layer will continue to grow and after many years, the wound may close over entirely.


Normal furrowed bark has a layer of bark over the wood below, however bark may peel or fall off the tree in sheets (river birch), plates (sycamore and pine), strips (cedar) or blocks (dogwood).

To reduce frost crack, avoid using fertilizers late in the growing season. Also, protect your trees from physical damage that can occur from lawn mowers, trimmers car bumpers, grazing animals, spades, etc. You can protect young trees in winter with paper tree wrap. Wrap your tree from ground level to the first main branches.

Trees most susceptible to frost cracking are: apple, crabapple, beech, cherry, golden-rain tree, horsechestnut, London planetree, some maples, pin Oak, tulip Tree, walnut, and willow. With the proper knowledge of what frost crack is and a few preventative measures, it is possible to try and protect your trees throughout the winter.

Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.

How Does A Tree Survive The Winter?

Have you ever wondered what happens to a tree in the winter months? Ansel Adams has made a living out of photographing the beauty of such trees; but what, truly, is going on inside these large pieces of nature?

Trees may look as if they are inactive going into winter, but they continue to regulate their metabolism. Early dormancy involves a number of factors: active growth, formation of buds, losing leaves and development of cold resistance. The buds of some trees have a winter chilling requirement for winter survival. Evidence from some experiments proves that chemical treatments immediately prior to the first frost may break winter rest for trees. So it is recommended that weed or growth killers for trees not be applied a few weeks prior to the temperature dropping to low levels.

As trees begin to lose their leaves, they are already preparing for the cold season. Leaves are a main source of light absorption, so trees must start building up a food and fertilization supply within the roots and branches to last throughout winter. This dormancy is triggered, in trees, by a number of factors: temperatures dropping, minimal nutrition gatherings and water supply.

Along with the naturally cold temperatures, excessive winds and ice that is all produced during the winter season, there are other variables that can determine a tree’s heath for next spring. As the temperature begins to drop, small animals such as snakes and rodents, are actively seeking winter shelters. Mass quantities of these animals within a tree can damage and even hollow a tree completely. Deer are also dependent on tree bark as a food source during the winter months. Paint-on repellents and mesh fencing can deter some of this activity, but trees may take an unhealthy turn when animals are consistently wearing on them.

Pruning a tree during late Fall can protect it from major branch breakage. As ice begins to build up on tree branches, the weight can often snap branches in half. Pruning dead or overlapping branches can strengthen a tree for winter. Even deadwood and ill branches should be removed and discarded of, for the health of a tree.

There are several dormant sprays that are available to protect your tree from Jack Frost. These sprays often contain copper, lime and sulfur. These protectants, with a nice top layer of mulch around the tree, may stop microorganisms from entering the tree. If sprays aren’t for you, there are several organic options to getting lime into the tree’s roots and base.

When it comes to your evergreens, be sure to keep them properly watered throughout the winter to reduce winter injury.. Never stress plants by under - or overwatering. Decrease watering slightly in September to encourage hardening off, and then water thoroughly in October until freeze-up. Watering only in late fall does not help reduce injury. If an evergreen has suffered winter injury, wait until mid-spring before pruning out injured foliage. Brown foliage is most likely dead and will not green up, but the buds, which are more cold hardy than foliage, will often grow and fill in areas where brown foliage was removed. If the buds have not survived, prune dead branches back to living tissue. Fertilize injured plants in early spring and water them well throughout the season. Provide appropriate protection the following winter.

Even though trees respond differently to winter stress and each winter provides a different set of stressful conditions, trees possess a remarkable ability to withstand extremely severe winter conditions.

Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.