Estimation of stand-level aboveground biomass dynamics using tree ring analysis in a Chinese fir plantation in Shitai County, Anhui Province, China

Chinese fir [(Cunninghamia lanceolata (Lamb.) Hook] is one of the most important plantation tree species in subtropical China, accounting for about 21 % of China's total forest plantation area. Although many studies have been conducted in Chinese fir plantations, uncertainties remain regarding its potential and dynamics to sequestrate carbon as a function of stand type, stand age and management. In this study, we applied tree ring analysis as a retrospective tool to study tree-and stand-level aboveground biomass (AGB) dynamics in a 17-year old Chinese fir plantation in Shitai County, Anhui Province, China. A total of 18 trees from different dominance classes were felled for the stem analyses: 6 dominant, 6 co-dominant and 6 suppressed trees. The stem analyses showed that as expected the annual increments of dbh and AGB were significantly higher for dominant trees than those for co-dominant and suppressed trees. Total stand-level AGB increased from 1.85 t ha(-1) at age 3 years to 108.12 t ha(-1) at age 17 years. Splitting the stand into dominance classes, tree analysis was useful to explain variation of the stand-level AGB and provided more detailed information about the growth dynamics of the stands. Tree ring analyses offer a viable and efficient approach to retrospectively study tree growth and AGB accumulation dynamics in Chinese fir plantations. In the studied stand under the given management regime, a rotation period of 17 years would optizimise AGB productivity.