by Olalla Diaz Yanez

This workshop was organized in the context of the PROCLIAS Task Group 2.3 on novel approaches to model uncertainty assessments.

The focus of the workshop was on tree regeneration. Tree regeneration is an essential ecological process in forest dynamics, but until now many vegetation models had represented this process based on limited data and without benchmarking their outputs against large datasets. We had the opportunity to use a unique long-term dataset from forest reserves across Europe that contained information on tree regeneration. This allowed us to test how different vegetation models created with diverse philosophies were able to reproduce tree regeneration dynamics, but also to better understand why some model structures are better suited than others, and possibly identify which formulations are more important when defining tree regeneration.

Before attending the workshop, the modelers simulated forest dynamics and collected their tree regeneration outputs using their own vegetation models. These simulations were prepared based on a protocol that was sent 4 months before the workshop and that contained the basic data for the models to set up the simulations. The modelling teams did not have access to the empirical data until a few days before the workshop, but the organizers provided continuous support and clear instructions to achieve a standardized simulation strategy across rather different models with several input data requirements.

The main objective of gathering all these modelling experts in a four-day workshop in Davos was then to explore the outcomes from the different models and explain why different model structures and complexities provided different results, and ultimately provide recommendations for future modelling of this important ecological process in forest dynamics. 

We consider this workshop a success because all the modelling teams were able to provide simulations before the workshop, the participants were extremely engaged, and the discussions and further work developed during the workshop have set a solid base to produce at least one publication that will be of interest for a wide modelling community. This publication will provide recommendations to enhance the robustness of dynamic vegetation models to study global change effects and climate impacts. The manuscript is currently under the last round of internal revision among the co-authors. Stay tuned for interesting results!

We very much thank EU COST Association and the COST Action CA19139 PROCLIAS for supporting this workshop.