A novel root inclusion net method was designed to determine the fine root productions and turnover rates of 13-, 22-, and 38-year-old Larix principis-rupprechtii plantations in the whole growing season of 2012, and it was compared with the results of the sequential coring method and in-growth core method. All following values are reported in order for 13-, 22-, and 38-year-old L. principis-rupprechtii plantations. The mean values of fine root biomasses were 103, 261, and 356 g m -2 , about 76-78% of which were live fine root biomasses. The fine root productions were 86-118 g m -2 year -1 , 124-138 g m -2 year -1 , and 134-160 g m -2 year -1 , respectively. The fine root turnover rates were 1.12, 0.61, and 0.51 times year -1 , respectively, suggesting a relative slow fine root turnover in L. principisrupprechtii plantations. The carbon inputs into soil accompanying fine root turnover were 52, 58, and 94 g C m -2 year -1 . This organic carbon is a sizeable pool in the forest ecosystem. The results suggest that our new modified root inclusion net method is suitable for field-based assessment of fine root production and turnover.