Key Features
- Wilted leaves
- Thinning of canopy
- Reduction in growth
Symptoms
All plants are susceptible to drought, but some species are especially susceptible, and include arborvitae, ash, aspen, cottonwood, birch, false-cypress, pine, spruce, and yew. Plant damage from drought typically starts at the top of the tree moving down. Also, outer areas show symptoms before the inner areas. Symptoms include wilting, decreased growth, thinning of the canopy, yellowing of leaves, forming of suckers, and wood or bark cracks.
Biology
Drought is a period without precipitation, during which the water content of the soil is reduced so that trees can no longer get sufficient moisture for normal processes. Long term drought describes conditions in which water deficits persist and occur over a period of several years, whereas short-term drought refers to a single season of water deficiency.
Management Recommendations
Supplemental watering during dry conditions is important for reducing the effects of drought stress. Water trees whenever rainfall is insufficient for extended periods, especially on newly planted trees and those less established. A proven recommendation is to use the 5 + 5 rule, which says to provide 5 gallons of water plus 5 gallons for every diameter inch of tree trunk. For mature and well-established trees, provide 1 inch of supplemental water every week to keep moisture adequate. It is advisable to water plants though the fall until the ground is frozen, so that trees have adequate moisture to survive the winter months and are ready for spring growth.
Effective Pesticides
Pesticides are neither available nor recommended for managing this condition.
Resources
