Leaf Temperature and Transpiration¹

Abstract

Synopsis The mechanisms which contribute to the energy exchange for a leaf are described and a graphical solution to the heat transfer equation for a leaf is presented. The importance of transpiration for cooling a leaf is shown in quantitative form. The complete energy budget for a leaf of Querous macrocarpa was observed at various times of day including radiation, convection, transpiration, and leaf temperature. It is shown that good agreement is realized between the energy absorbed by the leaf and the energy consumed by dissipative mechanisms.