Many regions in the country have been suffering through a prolonged drought. Recognizing a drought can be difficult if you have just moved to an area or are unaware of the long-term conditions. For example, the pattern and frequency of rainfall is measured to determine drought above the total amount of rain. An area can receive more rainfall in a year that is above normal levels and still be in a drought.
Recognizing an area affected by drought can simply occur through the symptoms trees and plants exhibit. Immediate visible effects of drought damage include wilting, scorch, and some defoliation due to loss of turgor in plant cells, irreversible shrinkage of cell membranes, and increased synthesis of abscisic acid. Long-term symptoms of drought include dieback of branches and death of the plant as the plants capacity to absorb water is damaged. These are the primary or direct effects of drought.
Secondary effects of drought include a plant or tree’s heightened susceptibility to disease and insect invasion. Disease and insect invasion can occur with any conditions but during a drought disease such as root rot, cankers, wood rot and wilt do increase.
If your trees are showing the following symptoms, it could be due to drought injury:
• Leaves that scorch and become brown on the outside edges or brown between veins.
• Leaves that wilt, curl at edges and yellow.
• Evergreens whose needles turn yellow, red or purple.
If your tree is suffering from drought there are some actions you can take to help keep it alive and healthy. The first includes proper watering. When watering your trees, water to a depth of twelve inches below the soil’s surface. This means you must saturate the soil within the dripline or the outer edges of the tree’s branches. For evergreens, water three to five feet beyond the dripline on all sides of the tree. You want to water your trees slowly, this allows the water to seep deep into the ground and not just run off the surface. Many people feel that if they dig holes in the ground, the water will seep deeper into it – when in fact, digging holes can just dry out your roots. Spraying your leaves is inefficient as well and should be avoided during a drought.
How much water do you give a tree during a drought? The rule of thumb is to use approximately 10 gallons of water per inch of trunk diameter, for each watering. Measure the tree’s trunk at knee height. The formula then follows – Tree Diameter x 5 minutes = Total Watering Time.
If you are using a hose, as most people do when watering, you may wonder how many gallons it will produce in a given amount of time. This can depend on your water pressure, but a hose at medium pressure will take approximately five minutes to produce ten gallons of water.
Trees should be watered year around with emphasis between April and September. Mulching around your tree will also help reduce moisture loss. It is recommended to use four inches of mulch. You can use wood chips, shredded bark, leaves or evergreen needles. One should avoid using stone or rock as it increases air temperatures and can add to the moisture loss. Place your mulch six inches from the trunk of the tree.
One should not fertilize a tree that is under drought stress. Fertilizers stimulate growth, which can result in too much leaf area on the plant for the root system to maintain.
To help maintain your tree’s health during a drought you will want to treat it as a sick patient. Care is needed such as keeping it free from stresses, keeping it properly pruned, and cutting back on any applications of herbicide in the root zone.
Taking special care of your tree during a drought will save you the time and money of having to remove it and replace. With just a little time invested, your trees can remain healthy and happy in all conditions.
About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit http://www.centraltexastreecare.com.