Abstract:In order to reveal the adaptation mechanism of fine root functional characters of Castanopsis fargesii to environmental changes, the relationship between functional traits of fine roots and soil factors of C. fargesii at 500, 700 and 900 m altitude in Guoyanshan was studied. The results showed that the fine root biomass was positively correlated with fine root length density, surface area density, tissue density and volume density. Fine root length density, volume density, surface area density and specific root length had significantly positive correlations each other, and which had significantly negative correlations with fine root tissue density. The contents of rhizosphere soil water, C and N had significant positive correlation with fine root specific root length, root length density, bulk density and surface area density, while those had positive correlation with soil bulk density and fine root tissue density. The fine root biomass, root length density, surface area density and volume density at altitude 700 m were significantly higher than those at 500 and 900 m. The root length density and surface area density were negatively correlated with soil depth at altitude 500 and 900 m; while the tissue density of fine roots at 500 m altitude was positively correlated with soil depth. Therefore, Castanopsis fargesii in Guoyanshan could change its fine root function traits in order to adapt to the changes in altitude and soil.