Computational and Experimental MechAnics of CAMbium – CEMACam

An important lever of climate change mitigation policies is the massive use of wood to replace more energy-intensive and non-recyclable materials. Its particular cellular structure makes it a sophisticated composite material with multiple uses under increasing diversification. Wood is also a huge carbon sink, accounting for more than half of the world's biomass. However, the basic physical mechanisms that govern the formation of wood by the cambium (cell division and enlargement) remain poorly understood. It has been shown in animal tissues and in the apical meristems of plants that the mechanical state of the cells plays a major role in these processes of cell division and expansion. However, the cambium is in a particular mechanical state; confined between the rigid tissues of the bark and of the xylem previously formed.
CEMACam will investigate the role of the mechanical state of the cambium in the cellular processes of wood formation. We will test two hypotheses: (H1) mechanical stresses imposed by the bark may influence growth by constraining cell expansion, and (H2) the local stress field in the cambium may determine the orientation of cell division planes. The study will require mechanical modelling at the tissue and cellular scales. The physical parameters required by the models, such as in situ turgor pressure or local mechanical properties, will be measured with original experimental devices thanks to the complementarity of the two teams that constitute the consortium and their collaborators.
The validations of the models will be done through original experiments. In particular, we will impose in situ controlled mechanical constraints on the cambium and compare the formation of the wood generated with the predictions of the models.
CEMACam aims to provide a new brick that could be a physical key to understand the mechanisms of wood morphogenesis.