The Extension Office has been busy with people coming in and sharing their "distressed tree" stories and samples, and wanting to learn what to do to remedy them. This time of year, as we all get outside more and begin to take a closer look at our trees, it becomes evident that a certain tree or two has had a rough winter, possibly being subjected to sub-zero temperatures, ice melt damage or a jagged break from heavy snow left on the branches.
What does a stressed tree look like?
Symptoms of stress in trees can be sudden or may take up to two years to be revealed:
- Drought injury symptoms on tree leaves include wilting, curling at the edges and yellowing.
- Deciduous leaves may develop scorch, brown outside edges or browning between veins.
- Evergreen needles may turn yellow, red or purple. They also may turn brown at the tips of the needles and browning may progress through the needle towards the twig.
- Leaves may be smaller than normal, drop prematurely or remain attached to the tree even though brown.
- Stress may not kill the tree outright, but it may set it up for more serious secondary insect and disease infestations in following years.
Where/how should you be watering your trees?
- Trees should be watered to a depth of 12" below the soil surface.
- Saturate the soil around the tree within the "dripline" (the outer edges of the trees branches) to disperse water down to all the tree's roots.
- For evergreens, water 3 to 5 feet beyond the dripline on all sides of the tree.
- The objective is to water slowly, dispersing the flow of water to get the water deep down to the trees roots. Watering for short periods only encourages shallow rooting which can lead to more damage.
- Overhead spraying of tree leaves is inefficient and should be avoided.
- Most people don't realize it, but evergreen trees need water year-round since they continue to grow throughout the winter and need moisture to survive. This can be tricky with all the hoses put away for the winter!
What kind of annual tree maintenance do trees need?
- Mulch around your trees with 4 inches of organic mulch to reduce moisture loss. Replenish as necessary to maintain this depth throughout the years. Avoid the use of stone or rock near trees as it increases the air temperatures and moisture loss from leaves and stems.
- Keep mulch about 6 inches in all directions away from the tree's trunk.
- Keep your trees healthy and pest free. Treat insect and disease problems at early onset to reduce the overall damage to the tree.
- Properly prune trees and shrubs to improve structure, limb stability and to remove dead and weak branches.
- Many tree species are harmed by herbicides used in the lawn. Avoid heavy applications of lawn chemicals near your tree's root zone.
Following these guidelines will help preserve your trees -- the most valuable asset to your landscape. For additional information, visit the "Save our Shade" Web site at www.watersaver.org/saveourshade.asp. The following free fact sheets are available:
- Caring For Trees in Dry Climates
- Watering Trees
- Hand Tree Watering Schedule (April-September)
For more information or help in identifying a tree disorder, contact your local Extension Office. In Moffat County--539 Barclay Street, 824-9180; Routt County--136 6th Street, 879-0825; Rio Blanco County--779 Sulphur Creek Rd, 878-9490.