When trees are affected by drought, symptoms include wilting, off-color foliage, twig and branch dieback in the crown, and the death of fine roots.
What is drought? In trees, drought symptoms are produced when loss of water through the leaves exceeds uptake of water by the roots. This is caused by inadequate soil moisture during extended periods of abnormally low rainfall.
Why is drought a concern? The death of fine roots can cause tree mortality by preventing the uptake of water even if moisture is restored to the soil. Crowns of drought stricken trees usually die from the top down and from the outside in. Trees in this condition are more readily attacked by fungi and insects. Shallow-rooted trees, and trees planted on light, sandy soils with poor moisture-holding capacity are most susceptible to drought. Conifers growing over high water tables for long periods may die quickly after the water table drops.
Visit the Forest Threat Summary Viewer to learn more about this and other forest threats.
Above: Drought symptoms in maple - Photo by Robert L. Anderson, USDA Forest Service, www.bugwood.org