It’s Cold and I’d Like a Sweater!

Cold, chilly temperatures are starting to set over the Front Range, reminding us that we need to wrap up in our thick winter sweaters and coats. While we protect ourselves, have you also thought about wrapping up your trees to protect them from winter weather?

Why should I wrap my trees?
Young trees have not developed a thick enough bark to insulate them from the extreme weather that winter can bring to Colorado. Tree wrap gives them that extra bit of protection which can often mean the difference between life or death.

What can happen to an unwrapped tree?
The most common winter injuries to young trees are sunscald, aka “Southwest Injury”, and frost cracks. Sunscald often occurs on the south or southwest side of the tree due to the location and angle of the sun during the winter. The low angle causes the trunk to heat up, causing once dormant cells to suddenly become active. As the sun sets or the weather changes, the temperature may drop below freezing which then kills the active cells and conductive tissues of the tree. This injury usually appears as sunken and discolored bark that can peel, crack, or fall off in patches later to reveal the dead tissue underneath.

These wounds take a long time to seal over and can leave the tree vulnerable to pests and diseases. Frost cracks can occur anywhere on the tree but are often found on the south or southwest side. Cracks begin to form when warm winter days cause cells to expand in the bark and internal layers of the tree. When the weather suddenly changes or the sun starts to set, the outer bark cools quickly but leaves the inside of the tree warm. This rapid cooling contracts the cells over the expanded cells, resulting in the bark and wood splitting or cracking. Frost cracks will take a shorter time to seal over than sunscald but will still leave the tree vulnerable as it is healing.

What trees need to have tree wrap?
Young thin-barked deciduous trees benefit the most from tree wrapping. The most common species are honeylocust, linden, maple, ash, ginkgo, and fruiting trees, but any young tree with thin bark can benefit. Trees with thick, cork-like bark, such as bur oak, do not need to be wrapped.

When should I wrap my trees?
Trees should be wrapped by the end of November through early spring (mid-April) when sudden frosts are no longer an issue. Due to the varying temperatures in the Front Range of Colorado, you may want to wrap your trees as early as October or keep them wrapped until mid-May depending on weather.

How do I wrap my trees?
To begin, use a light-colored commercial tree wrap. Plastic, dark colors, or burlap could potentially result in tree damage. A good choice would be crepe-paper, which has some elasticity and sheds water, keeping the trunk dry. Start tightly wrapping at the bottom of the tree in an upward spiral pattern, overlapping by 1/3 every spiral until you reach the first branch. Try to make it tight enough that it holds on well to the tree, but not so tight that you damage the wrap. When you’re done, tape the wrap to itself to prevent it from slipping. Remember to not tape the wrap to the tree! Our goal is to prevent damage, not potentially cause it. Tree wrap will need to be removed in the spring. Leaving the wrap on all year will restrict tree growth and result in girdling injuries. If left on throughout summer, it can be a residence for insects and diseases that could potentially harm your tree. As a less expensive method, you can also paint the trunks with a white water-based latex paint (diluted to about 50/50 paint to water). The paint is best applied at temperatures above 50F for fast drying. The downsides of this method are that it is less aesthetically pleasing and will take time to wear off.

How long do I need to wrap trees?
Trees will only need to be wrapped for 1-3 years following planting, depending on how fast the bark hardens and becomes furrowed. Consider this a seasonal treatment for the health of your trees.

What else can I do to help my trees?
Fertilizing and adding mulch around your trees are great ways to help them stay healthy. Also consider irrigating your trees during drier winters, especially young trees, to help them be less susceptible to damage.

While Bailey Tree does not offer tree wrapping services, we do offer a variety of ways to help you keep your trees healthy. From trimming to fertilizing to winter watering, let our ISA Certified Arborists help you take the labor and guess work out of your hands to keep your landscape protected and beautiful.