One common winter related tree issue in Calgary is winter desiccation (AKA winter drying). Winter desiccation occurs when the needles of evergreens are exposed to high winds and low temperatures. They dry out quickly because the ground is frozen and the tree is unable to replace the water lost from the foliage through evaporation. We see more damage related to this issue in some years than we do others. It is a common issue in Alberta, especially in trees with shallow roots like Spruce. Many trees will fully recover once new foliage develops in the spring.
Most trees can be affected however we typically see this issue affect Spruce, Pine, Fir and some smaller evergreens like Juniper and Cedar. Needles and Scales will turn a reddish brown color.
Prevention
Deep watering is the most effective way to prevent winter desiccation, because it is a result of over drying. Proper watering through the Spring and Summer months helps keep trees healthy and ready for winter weather. A deep watering before ground freezes is also very important in ensuring there is moisture available whenever temperatures rise. For tips on how and when to water see this link: Watering Landscape Trees in Calgary
Mulching is another preventative measure that can be taken. A four to six inch layer of mulch around your tree’s root zone will protect from water loss and help buffer temperature extremes
Control Measures
Despite preventative measures, winter desiccation is hard to completely avoid if you have many trees susceptible to injury. Prune only after new growth has developed as it is not obvious what might survive the damage until the new growth has emerged. Once new growth has started,dead branches and tips can be removed.
What about painting the needles white with a paint that will wash off with a few rains?
No. We would never recommend applying paint to the foliage of a tree. There are many pores in each needle that could allow toxic material into the plant.
Nicely written! Most people do not realize if their trees have evergreen desiccation.