Measuring plants is surprisingly controversial, and often very difficult. Consider, for example, deciding how to measure the size of a leaf: include the petiole or not? if there are multiple leaflets? if the leaf is ten meters long? Ask ten ecologists and you will likely hear ten different answers, all of which may seem appropriate in each ecologist’s study system. This variation makes it very difficult to synthesize results or simply get multiple scientists to work together in the field.
One area this especially relevant is climate change models. These complex simulations are beginning to use quantitative measurements of leaf properties to predict future changes in Earth’s vegetation. The output of these simulations is only as accurate as the inputs, so noise in the input data (arising only from variation in field methods) can be carried through the models into large and unwelcome uncertainties in future vegetation.
Fortunately the ecological community has come together to standardize our methods and protocols. The first major effort was the Cornelissen et al. 2003 handbook, which has been cited almost 800 times since its original publication. However many new variables have been identified since the first handbook was published, and many methods have changed as the field became more mature. A new handbook was begun several years ago, and I was fortunate enough to be invited by Sandra Diaz to contribute a section on leaf venation.
The new publication is nearly seventy pages long, and you can read it (Perez-Harguindeguy et al. 2013) in the Australian Journal of Botany.
The handbook is already proving useful. Here in the Andes, our project began with a multi-day ‘trait course’ for dozens of Peruvian students who will be working in the field for the next several months. Here you can see Sandra Diaz giving a lecture on leaf physiology.
These new standard protocols are being used in the field – for example, in these photosynthesis measurements in the cloud forest,
and in these tree-climbing operations to seek ‘sun’ leaves from the high canopy.
The handbook has taken two years to be written, with much time needed for all the authors to come to consensus on what the community consensus should be. But seeing the protocols in action makes the extended effort (mostly of Natalia Perez-Harguindeguy, the first author of the handbook) of everyone worthwhile. These standardized data will be the foundation of a much stronger ecology to come.