Abstract: Measurements for C.eyrei forests with different stand ages in Wuyi Mountains show that in mature stand forest, the biomass, production and decomposition of fine roots were 10.645t·hm^-2, 7.3715t·hm^-2 ·yr.^-1 and 4.6775t·hm^-2 ·yr.^-1 respectively, with a yearly turnover rate of 0.69 time.The biomass and production of fine roots varied with stand age, reaching their peaks at 34 and 58 years respectively.In the mature stand forest, the Nreturn by fine root decomposition contributed 49.5% of the yearly total Nreturn, more than that by litterfall; Pand Mg returns derived from dead fine root were 42.3% and 28.9% respectively, less than those from litterfall; and Kand Ca returns were mainly came from canopy, secondly from litterfall, and only 19.3% and 9.2%, respectively from fine roots.

Key words: Fine root, Biomass, Turnover rate, Stand age, Castanopsis eyrei forest, Wuyi Mountains, Phragmites australis, Tamarix ramosissima, soil enzyme, growth period