Assessment of inter-annual forest production variations in Italy by the use of remote sensing and ancillary data

The application of Monteith’s models to estimate the gross primary production (GPP) of forest ecosystems is a common and efficient practice. A modified version of one of these parametric models, C-Fix, has been widely tested in Italy at daily to annual temporal scales. The current paper is a step forward towards demonstrating the capability of this model to reproduce also inter-annual forest GPP variations. To this aim, dendrochronological measurements collected in two study areas are utilised to validate the model. The first study area corresponds to a coastal Mediterranean pine forest and the second to a more temperate ecosystem dominated by the presence of European beech. The experiment is organised into the following main steps. Modified C-Fix is applied to simulate annual GPP over a fifteen-year period for both sites. The main driving factors used by the model are first analysed to assess their influence on forest production; next, the estimated inter-annual GPP variations are evaluated against the tree-ring widths of the collected cores. The study yields indications on the most influential factors for the two forest ecosystems and supports the capability of the proposed modelling approach to reproduce relevant inter-annual GPP variations, providing an analytical tool for predicting the impacts of ongoing climatic changes.