many neotropical forests there is little evidence thatthis is a pan tropical phenomenon and we have little knowledge of the conditions where they are increasing the fastest (4). Understanding the causes of liana increases and where lianas are increasing most rapidly will become crucial for modeling future effects of lianas on forest carbon dynamics. Finally global vegetation models themselves will benefit from further development and refinement. The inclusion of a greater diver-sity of plant functional traits in global models (6) for example may be critical to improving these models and for predicting how lianas affect future carbon dynamics and storage in tropical forests.The best way to address the challenges of in-corporating lianas in global vegetation models is to establish a network of observational and experimental studies on the effects of lianas in a variety of forest types throughout the tropics. Although empirical data from recent experimental studies (2 3) can certainly provide initial parameter estimates for refined global vegetation models long-term data from across the tropics will provide a much more robust solution to the current challenges of accurately parameterizing global vegetation models.