In relation to the linkage between physiological and ecosystem functions of fine roots in tree species, this article is reviewed from our work about forming and maintenance processes of fine root architecture in Hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.). Apical roots are higher in physiological activities than the basal roots, because of not only aging, but also ontogenetic difference, ‘heterorhizy’. These physiological functions affect the demography of individual roots within a fine root architecture, i.e., mortality rate is higher in apical roots than in a basal roots. Moreover, apical roots tend to die before secondary growth, whereas basal roots tend to die after secondary growth. These life cycle processes relate with decomposition rates. Thus, the heterorhizic fine root architecture is important not only for physiological functions but also for ecosystem functions. Further studies in plasticity of fine root architecture among inter- or intra-species to environmental factors will be needed to reveal the linkage between physiological and ecosystem functions of fine roots.