Analysing the effects of local environment on the source-sink balance of Cecropia sciadophylla: a new methodology based on model inversion

• Functional-structural model (FSM) of tree growth have great potentials for the forestry field but their development, calibration and validation are hampled by the difficulty to collect experimental data at organ scale for adult trees. Owing to their simple architecture and morphological properties, 'model plants' such as Cecropia sciadophylla are of great interest to validate new models and methodologies since exhaustive descriptions of the plant structure and mass partitioning are accessible. • The objective of this study was to propose a methodology and to analyse the influence of environmental conditions on the dynamics of trophic competition within the trees. • Using data of 11 trees measured in September 2007 for calibration and data of 7 trees measured in December 2008 for validation, we present a method to estimate an integrated factor of local environment for each plant, based on model inversion of the GreenLab FSM. It provides as a result the complex dynamics of biomass allocation to the different components of the plants during their growth, according to the environmental pressure they underwent. • Extension of the model to population level could be done by linking the integrated environment factor to a competition index.