Detecting leaf necrosis and branch dieback of transplantation-shocked kousa dogwood trees by thermography

Abstract

Leaf necrosis and branch dieback of the newly transplanted dogwood trees triggered by the prolonged dried period and sudden rise in temperature was observed in the study. Attached and detached leaves and branches were detected by a thermo infrared camera under the conditions including outdoor environment, indoor window sunlight and incandescent light. Different thermo imaging characteristics were found between necrotic part and living part of both leaves and branches. The detection of the outdoor attached leaves indicated higher temperatures at the necrotic part than living part, seemingly being attributable to the high water content and transpiration cooling effect in the living part. However, the detached leaves change their temperatures at necrotic part faster than that of living part, largely due to the lower water content. Significantly amplified variation of imaging temperature between the live and dead parts of detached leaves and branches during the heating and cooling process indicated that there was potential to detect the leaf necrosis and branch dieback by viewing the temperature fluctuation of Kousa dogwood (Cornus kousa) trees with thermography.