Drought-sensitivity ranking of deciduous tree species based on thermal imaging of forest canopies

► We show infrared thermometry and sap flow data of six deciduous tree species. ► Species with dense canopies were considerably warmer especially at dry sites. ► Under drought, diffuse-porous-wood species show a strong reduction in sap flow. ► The sap flow of the two ring-porous species was not affected by prolonged drought. ► Based on the data we ranked the species according to their drought sensitivity.