Forest ecosystems are important because of the key role in reducing atmospheric greenhouse gas concentrations by storing a large amount of carbon in biomass and soils. The relative amount of above-ground biomass allocated among different tree tissues is a functional indicator of forests' health reflecting the material flow, the wood quality and the plant survival strategy. The way in which plants steer their photosynthetic product across their compartments is not fixed but likely vary over time, across growth economies and among species and, lastly, is influenced by plant size and climate, Obtaining a qualitative/quantitative understanding of the influence that these factors have in both growth and biomass allocation is of fundamental importance either in understanding plant ecology and evolution and into developing environmental policies and useful forest management practices to cope with future climate change.