The research focuses on the study of the physiological mechanisms involved in the wood formation (xylogenesis) in forest species. The cambium is the meristem producing wood and it has a double meaning: a) yield (the cambium produces biomass), b) ecological (the the carbon fixed by leaf is stored in the wood by cambium). Understanding the physiological mechanisms regulating the cambium activity and cell differentiation is a key step for improving the productivity of plantations (arboriculture) and to define predictive models of forest productivity in a perspective of global change . In our studies, the cambium represents a biological model in which growth (cell division) and differentiation (cell expansion, lignification and programmed cell death) are investigated in space and time by anatomical, biochemical and molecular analyses. The main goal of this approach is to understand how and how much the cambium activity and xylem formation can be modulated by environmental changes. Through the development of a siutable protocol for extracting cambial region (Giovannelli et al., 2011), intrannual analysis of stem growth (Giovannelli et al., 2007) and new experimental tools (Emiliani et al., 2010 ) is possible to investigate the effect of some environmental parameters (mainly temperature and water) on the cambium phenology and the intrannual dynamic of wood formation. The effect of water deficit is investigated in poplar (model species) to study in the cambial region: 1) the dynamics of growth and development of secondary meristems, 2) the source-sink relationships for carbon (non-structural carbohydrates); 3) the expression of the genes involved in the antioxidant defence system (scavenging) and the network of genes involved in response to water stress (microarray), 4) the hydraulic architecture of the xylem. The effect of temperature variations is studied along altitudinal gradients in Trentino (Picea abies), latitudinal gradients in Quebec (Picea mariana), with heating system of the stem (Picea abies) and in a controlled environment (Picea mariana).