Tree Heat Stress Syndrome
University Outreach Publication
Georgia can have many hot days during the year. From the North Georgia mountains to the coast, these large heat loads can influence plant growth. Figure #l ; Figure #2. Trees and shrubs generally have optimum growing conditions across the range of temperatures from 70°F to 85°F Hot temperatures can injure and kill living plant systems.
A thermal death threshold is reached at approximately 115°F. The thermal death threshold varies depending upon the duration of hot temperatures, the absolute highest temperature reached, tissue age, thermal mass, water content of tissue, and ability of the plant to make adjustments to temperature changes.
A plant’s temperature usually runs just above air temperature. Plants dissipate heat by longwave radiation, convection of heat into the air, and transpiration (water loss from leaves). Transpiration is a major mechanism of plant cooling. Without transpirational cooling, heat radiated to the surroundings and wind cooling are the only means of keeping plant temperatures near air temperatures. Sometimes radiated heat and hot breezes prevent heat dissipation and add to the plant’s heat load.
(FOR96-025) July 1996
Kim D. Coder
1996
University of Georgia School of Forest Resources
Athens, Ga
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Abiotic Factors, Best Management Practices (BMPs), Ecological Restoration, Energy Conservation, Evapotranspiration, Forest Health, Fragmentation/Parcelization, Health (tree), Heat Island, Impervious Surfaces/Cover, Infrastructure (gray), Infrastructure (green), Integrated Pest Management (IPM), Land Development, Landscape Ecology, Plant Health Care, Site Evaluation/Selection, Stress & Stressors
National
Heat load, Heat stress syndrome, Heat stroke, Tree heat loading
