On a technical note it has become very simple to record the thermal characteristics
of a habitat at very little cost and effort. Robust, waterproof data loggers of the size
of a coin are available for less than €100. If buried in the meristematic zone of
grassland plants or exposed in full shade of tall vegetation, year round temperatures
can be recorded at high temporal resolution (examples for the usefulness of such
records are in K¨orner & Paulsen, 2004). There is only one precaution: the sun must
never hit such devices. The true leaf surface temperature will thus remain unknown.
The best devices to obtain such surface temperatures are high-resolution digital
thermal cameras as the one used for producing Colour Plate 4 (for a review of such
techniques consult Jones et al., 2003; Jones & Leinonen, 2003).