Positive interactions between Pinus massoniana and Castanopsis hystrix species in the uneven-aged mixed plantations can produce more ecosystem carbon in subtropical China

Abstract

Abstract Silvicultural practices are an important determinant of tree growth and stand structure. However, the potential advantages of long-term forest management, i.e., mixing valuable non-N 2 -fixing broadleaf tree species, such as Castanopsis hystrix Miq., with Masson pine ( Pinus massoniana Lamb.) to increase stand growth and ecosystem carbon storage, remain poorly understood. In this study, we assessed tree growth, aboveground carbon accumulation, and belowground carbon sequestration in 26-year-old monocultures of C . hystrix ( 100 C 26 ), 26-year-old monocultures of P . massoniana ( 100 P 26 ), 50-year-old monocultures of P . massoniana ( 100 P 50 ), and even- and uneven-aged ( 50 C 26 + 50 P 26 and 50 C 26 + 50 P 50 , respectively) mixed plantations. Carbon storage within the total ecosystem and in the tree and soil layers of 50 C 26 + 50 P 50 mixed plantations was significantly greater than values predicted based on the means of the 100 C 26 and 100 P 50 monoculture plantations ( p 50 C 26 + 50 P 26 mixed plantation soils. These results indicate that plantations of uneven-aged mixtures of P . massoniana and C . hystrix promote carbon sequestration via positive interactions.