Effects of different rotations on carbon sequestration in Chinese fir plantations

Aims Under the context of global climate change, scientific management is the main way to enhance carbon sequestration of plantation forests. A reasonable rotation is one of the intensive management strategies, adjusting forest structure. The decline of productivity after continuous multigenerational cultivation is strongly related to its rotation. Therefore, it is necessary to study the effects of different rotations on carbon sequestration of Chinese fir (Cunninghamia lanceolata) plantations, which can provide a theoretical basis for their sustainable management.
Methods We set up sampling fields of Chinese fir plantations with different age sequences, and used the observation data to test the FORECAST model. We then simulated the effects of different rotations on Chinese fir plantations sequestration using FORECAST model.
Important findings The results showed that over a 150-year period, total carbon sequestration was highest under short rotation length (15-year). However the carbon persistence was poorest and the decline of carbon between each rotation was biggest, indicating an unsustainable management model. Compared with short rotation, the total carbon sequestration under normal rotation (25-year) and long rotation (50-year) was lower. However, the carbon persistence under long rotation was strongest, which was beneficial to maintaining carbon stability during each rotation. Under good site conditions (site index (SI) = 27), the shorter the rotation was, the more severely the soil fertility was consumed. In order to have persistent carbon sequestration rates in Chinese fir plantations, we suggest that rotation should be longer than 25 years. Application of FORECAST model can help quantitatively assess carbon sequestration capacity of forest plantations, which varies under different management strategies.