Drought Stress
On Tree Health

August 14, 2003 -- Drought can have a significant impact on tree health. It reduces carbohydrate production, which significantly lowers the energy reserves and production of defense chemicals in the tree. If drought is acute enough or prolonged, it also can cause death to all or a portion of the tree. In most situations, drought weakens the tree and it becomes susceptible to disease and insect infestation that normally cannot invade a healthy tree. (This type of decline is also brought on by over-trimming.)

Chemistry (chemicals are involved)

Cellular metabolism slows, photosynthesis is reduced, there is less CO2 absorption and less enzyme activity. This lowers food production and leaves less food for growth and storage. This lack of storage causes defense chemicals to be reduced, leaving the tree's immune system low and making it more vulnerable to bacteria and insects.

Insects and Disease

Trees for the most part can resist the tiny predators when they are healthy. Attack by borers is the most common insect event associated with drought stress. Borers deposit their eggs in the vascular system of the tree. As they mature in size they reduce the flow of nutrients to the outer portions of the tree, causing die back. (This is like the clogging of our arteries). There are many bacteria, funguses and molds that attack weak trees. If the tree's immune system is low enough, this attack will also cause death. This does not mean water your trees every day. There is a solution, you can contact us, or use our website, which is an educational website to help you make decisions about your trees.

Santa Ynez Valley Tree Care
P.O. Box 1147, Santa Ynez, California 93460

(805) 688-5580

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