Leaf and canopy energy budgets

The plant in a field of energy, or in any considered area in which gradients exist, reacts passively to its surroundings . . . it should be clear that the sun, or even outer space, is not more removed from the plant than the next millimeter of air; it is the specific part of heat exchange being considered that determines what should be included in the plant’s environment.Klaus Raschke (1960)