Figure 1 . Diagram of the system used to measure leaf boundary layer conductance in this study. (a) General layout. (b) Positions of components during heating of the leaf and calibration of the infrared camera: the camera is centered over the window into the black body, the air temperature/wind speed sensor shield is in place over the sensor, and the heat lamp is positioned over the leaf. (c) Positions of components during measurement of a cooling curve: the camera is positioned over the leaf, the heat lamp is rotated out of the way (positioned in the same plane as the leaf, and radiatively shielded using mylar-coated bubble wrap), and the sensor shield is moved back from below the leaf.