Trees are an important part of your landscape investment. And with the dramatic temperatures we experience in Colorado Springs and the surrounding areas, it’s important to know how to prevent, recognize, and treat damage caused by severe weather.
Sometimes, no matter what preventative measures you take, a severe weather event can kill your tree suddenly without warning or take several years to show irreversible signs of damage.
This sudden and unpredictable damage doesn’t mean you shouldn’t invest in trees to make your landscape beautiful. It just means you should take preventative measures to keep your trees stress-free and know that sometimes tree loss is unpreventable.
Timberline Landscaping’s Certified Arborists put together this guide to help you understand freeze damage to trees in Colorado. You’ll learn:
- How the Cold Weather Damages Trees
- Tree Stress: Signs and Prevention
- The Signs of Tree Damage from Freeze Events
- Tree Damage Treatment
Freeze Damage to Trees in Colorado: How it Happens
Many people assume that the most common cause of cold damage to trees is extremely low temperatures. Actually, the most common cause of cold damage to trees is from extreme temperature fluctuations instead of just freezing temperatures in general. Here’s how:
- EXTREMELY COLD WEATHER: When temperatures slowly drop and progress into freezing temperatures over a long period of time, it allows trees to “harden off” meaning that the tree becomes acclimated to the freezing temperatures. They toughen up and naturally protect their tissue as winter approaches. Some plants do have a minimum tolerance temperature and will be damaged if the temperature falls below that level, but this is not the most common cause of tree damage.
- EXTREME TEMPERATURE FLUCTUATION: This is the most common freeze damage to trees. When there is an extreme temperature fluctuation of warm weather to freezing weather within a very short period of time, trees do not get the necessary time to harden off. In these cases, there can be severe damage to the tree’s tissue. An example of this is the freeze on October 10, 2019. Within a 24 hour period, the temperature dropped more than 60 degrees from a warm day to snow. The damage to trees ranged from mild to severe and even total tree loss. Some damage may not even show until spring or even later.
Commonly Freeze Injured Trees & Shrubs:
- Ponderosa pine
- Austrian pine
- Bosnian pine
- Vander Wolf Pine
- Ornamental Spruce’s
- Brooms, mostly north
- Rose of Sharon
Note: This is not an extensive list of all the trees/shrubs/plants that can be injured by freezes.
Tree Stress: Signs and Prevention
Tree stress is an important next step to address because stressed trees suffer more damage from freezes than healthy trees. Preventing and managing tree stress is the first step to take to help your trees survive freezing temperatures.
If a tree is already stressed and then an extreme temperature fluctuation occurs, you are more likely to lose that tree. These temperature fluctuations will inevitably cause stress to trees even if they are in pristine condition so use the following list of tree stress factors to give your trees a fighting chance:
Dry winters and hot summers in Colorado Springs and the surrounding areas can cause extreme stress to trees. Signs of drought-stress include heat scorch, decline, and dieback.
Prevention of drought-stress:
- Proper watering: Watering your trees too much can be just as damaging as not watering them enough.
- Winter watering: Follow these instructions on winter watering to prevent drought-stress during the winter.
Not Utilizing Pruning as Preventative Care
Many people forget about their trees during the winter and choose to take care of pruning in the spring and early summer. In some cases, this may be too late and attract harmful insects.
Prevention of pruning related stress:
- Winter is the best time to prune many trees because they are dormant. If you’re unsure of when the best time to prune your type of trees, contact your local arborist to find out.
- Pruning can encourage more vigorous growth and reduce pest problems.
Bug Problems and Diseases
Many bug problems and diseases occur on trees that are already showing signs of stress and suffering from deficiencies. If you notice disease or bugs on your trees, it is imperative that you act fast and involve a tree care professional to help correct the problem.
Prevention of bugs and diseases:
- Limit factors contributing to tree stress: poor planting techniques, soil compaction, nutrient deficiencies, lack of sun and water.
- Control current insect and disease problems with a tree professional.
- Fertilization and root treatments help keep trees healthy.
Inherently, younger trees are at more risk for stress because they have smaller branches more prone to breakage, a less complex root system, and have very specific water requirements. During the first three years, newly planted trees require special attention.
Preventing stress in young trees:
- Supplemental watering in addition to an irrigation system may be necessary for new trees.
- Mist leaves and needles of new trees during drought conditions.
The Signs of Tree Damage from Freeze Events
Although sudden temperature fluctuations and deep freezes are unavoidable, it is important to be proactive by preventing tree stress. When these weather events occur, it is important to monitor trees and act quickly if they are showing signs of damage.
A severe weather event can cause severe damage the doesn’t show until next season or even years later so it is important to check trees regularly, even if a severe weather event has not occurred for some time.
The following are some signs of freeze damage to watch for. (Note: This list contains only some of the common signs of tree damage. You know your trees best. When something looks off, contact a tree care professional.)
A frost crack on your tree will occur from a severe temperature fluctuation. Frost cracks typically happen on the south side of trees in Colorado. This is because during a warm day, the sun heats the south side. As the temperature drops rapidly, the outer layer of wood contracts faster than the inner layers and causes a crack in the trunk.
Even if you do not see a frost crack present on your tree, it does not mean that there is no damage. With a severe temperature drop, since the tree has not hardened off, there is still a lot of water and nutrients being conducted through the tree. The freeze can damage this tissue internally and cause stress in the tree. There is no telling how quickly this stress will reveal itself. Routine tree checks are a great way to help catch the damage, when possible, before it’s too late.
Sometimes, after a severe weather event, evergreen needles will quickly turn from their normal green color to a light bleached yellow. This can occur as soon as 10 days after the freeze event.
This is an indication of freeze stress and damage. It is typically difficult to tell if these needles will make a full recovery as it depends on the severity of the freeze among other factors.
Some trees to watch for bleached needles on are mugo pine, spruce, Vanderwolf pine, ponderosa pine, and Austrian pine. All evergreens may be affected on some level.
Blackened leaves on deciduous trees can also be caused by extreme temperature fluctuations. In the spring, trees can start growing leaves before an unexpected late freeze. In some cases, all of the leaves may turn black or brown and fall off.
If this happens early in the season, there is typically enough time for the leaves to grow back. This will depend on other factors including the tree’s age and health.
Damage similar to this can also occur in the fall and early winter. Your tree care professional can help you evaluate the damage but typically won’t know the severity until the tree leafs out in the spring.
- It is always a good idea to have mulch around trees. Extremely low temperatures can damage roots but mulch can help retain heat and prevent or reduce this type of damage.
- Proper plant health care is a great offense and defense for protecting your trees from freeze damage. Plant health care involves proper watering, deep root fertilizing, soil amendments, pruning, etc. Contact a certified arborist to create a plant health care plan for your trees.
Even though we can’t avoid or prevent severe freeze events and temperature fluctuations, it is important to protect your trees. Even though damage can be immediate or take years to show, taking preventative action to keep your trees happy is necessary to prepare.
There is no guarantee when it comes to the longevity of your trees but working with a certified arborist, checking your trees often, and watering them properly can help. Use this Freeze Damage to Trees in Colorado guide to help your trees stay stress-free and live long healthy lives.
If you notice severe tree damage after a storm, contact our certified tree professionals today.