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2/35Abstract 21We developed a double-digitizing method combining a hand-held electromagnetic digitizer 22 and a non-contact three-dimensional (3D) laser scanner. The former was used to record the 23 positions of all leaves in a tree and orientation angles of their lamina. The latter served to 24 obtain the morphology of leaves sampled in the tree. As the scanner outputs a cloud of points, 25 software was developed to reconstruct non-planar (NP) leaves composed of triangles, and to 26 compute numerical shape parameters: midrib curvature, torsion and transversal curvature of 27 the lamina. Combination of both methods allowed building 3D virtual trees with NP leaves. 28The method was applied to young beech trees (Fagus sylvatica) selected in different sunlight 29 environments (from 1 to 100% of incident light) in forest of central France. Leaf morphology 30 responded to light availability, with more bent shape in well lit leaves. Light interception at 31 the leaf scale by NP leaves was decreased from 4 to 10%, for shaded and sunlit leaves 32 compared to planar leaves. At the tree scale, light interception by trees made of NP leaves was 33 decreased by 1 to 3% for 100% to 1% light, respectively. 34 35

International audienceInsect pest development is often linearly related to air temperature, without taking into account the multiple interactions between the particular host plant and pest, the microclimatic conditions actually experienced by the insect, and the non-linear response of insect development rate to temperature. In this study, using an integrative biophysical model, we have investigated effects of both climatic and tree structure changes on the development of a phytophagous leaf mining moth (Phyllonorycter blancardella), taking into account the heterogeneous microclimatic conditions provided by its host plant, the domestic apple (Malus domestica), the larval body temperature rather than the ambient air temperature, and a non-linear development rate model. Hourly body temperature dynamics of larvae homogeneously dispersed in tree canopies were simulated from hourly meteorological conditions (medium IPCC climate change scenario) within the canopy of apple trees. To analyse the effect of tree architecture on leaf miner development, both pruned and unpruned trees, and one, two and three scaffold branched trees were used. Body temperature dynamics was used to compute larval development time and mortality following the non-linear developmental model for this insect. The results showed that tree pruning influences significantly larval development time and mortality. Nevertheless, the effects of manipulating tree structure on larval development and survival were relatively weak compared with the impact of chosen climate variations. This survey also showed that the variability in insect development time within a year and insect mortality change markedly with climatic variations, and highlights the importance of using non-linear rate curves and insect body temperatures instead of air temperature in forecasting models of climate-related insect pest outbreaks