Résumé
On an agroforestry plot, the services provided by trees are numerous, especially on the economic front since they help to improve the business model of the farm by diversifying activities and income for the farmer. However, agroforestry trees grow in very different conditions than forestry trees mainly because of their higher exposure to wind and light, specific competition for water availability, strong interactions with annual crops, numerous human operations on branches (pruning) and root systems(due to the tillage). Production level and quality such as anatomical, chemical and technological properties of wood coming from agroforestry systems have not yet been studied. Such results could provide many interesting data to the farmers to promote access of agroforestry wood to conventional and/or niche markets. This work started in January 2020 and is divided into two main axes: on one hand, we aim to understand how agroforestry trees adjust to their specific growing conditions, and on the other hand, we aim to study how these growing conditions affect the quality of the wood. As well as the annual wood productivity level, the notion of wood quality, which is very important because it influences the potential valorisation ways of the woods, may allow to improve their economical values. In our study, the wood quality will be addressed by considering the two following aspects: the mechanical performances and the biochemical composition. Two species are studied: hybrid walnut (Juglans x regia x nigra NG 23xRA) for the high aesthetic value in the wood market and poplar (Poplar sp) for the packaging and building market. The work is conducted by comparing, for each species, the growth and quality of wood from agroforestry trees with that from trees grown under more conventional conditions in terms of stand densities.