In this story on the Denver Post, Davey Tree gives some tips on how to recognize the signs of drought and how to help your trees survive a drought.
Published July 11, 2013.
Colorado's trees are coping with a stressful situation: multiple years of severe drought. Prolonged lack of water and dry soil conditions significantly reduce the life span of our valuable trees.
The current US Seasonal Drought Outlook map shows that a substantial part of the country remains in a persistent drought period, meaning the drought will continue or intensify. Even after periods of regular rain, trees can still suffer from problems related to prolonged drought.
Yet, the symptoms are easy to spot. Trees suffering from short-term drought stress often have wilted, drooping, or curling leaves that may turn brown at the tips or edges. You may notice a sparse canopy of off-color and undersized leaves, leaf scorch, or yellowing. Premature fall color and early leaf drop are also common in trees under stress from drought. Closer inspection may reveal limited twig growth coupled with small, poorly-formed buds.
Many trees can take up to three years after a drought to display negative long-term effects. Trees may suffer stunted growth, branch die-back, and possible death despite the return of sufficient rainfall.
Pest problems are another possible result of long-term drought. Stressed trees are more vulnerable to damage from certain insects and diseases. Pests such as canker diseases and certain borers can take advantage of stressed trees. Consequently, as a tree or shrub becomes weakened from drought, these pests invade rapidly.
While no one can predict how long this drought will continue, we do know that droughts will occur periodically over time, so its always a good idea to learn how to care for trees during this period of stress. Caring for trees is much easier, cost efficient, and environmentally friendly than replacing neglected trees.
These tree maintenance procedures can significantly increase a tree’s chance of making it through drought periods:
• In the absence of rainfall, water tree roots slowly once or twice a week allowing saturation of the upper 12 inches of soil. Making sure to follow your local irrigation ordinance. Concentrate on those areas directly beneath the foliage and shaded by the tree known as the “drip zone.”
• The best time to water is in the morning. Run a sprinkler beneath the tree as slowly as possible or use a drip hose. Avoid directly irrigating the trunk of the tree, as the increased moisture can favor root rot disease.
• Watering only those areas directly beneath the foliage and shaded by the tree known as the “drip zone” will also help.
• A Davey Tree care tip: place a coffee or soup can in the “drip zone” and run the sprinkler slowly until two inches of water has collected in the can. Tree roots are deeper than turf roots, so you need to water about three times as long as you water your lawn to make sure enough moisture reaches the root zone. You should be able to easily insert a long screwdriver 6-8 inches into the ground.
• Mulch two to four inches around your trees to reduce moisture loss, but do NOT volcano mulch. Mulch should be pulled back 6” from the trunk of the tree.
• Choose the right trees for your location.
• Keep your trees healthy and pest free. If your tree has any insect or disease problem that may be adding additional stress, treat them accordingly to reduce overall tree stress.
• Properly prune trees and shrubs during time of drought to improve structure, limb stability, and to remove dead and weakened branches. Leaving broken, dead, insect-infested, or diseased branches can further weaken a tree during drought and set the tree up for deadly secondary insect and disease problems.
Following these guidelines will help in the preservation of your beloved trees, the most valuable asset in the landscape. The good news is that trees can recover with a little help. If you have any questions, the certified arborists at Davey Tree are happy to talk with you.