ECOSYSTEM CARBON POOLS IN MIXED STANDS OF HARDWOOD SPECIES AND MASSON PINE

Abstract

FAN HB, LIU WF, WU JP, LI YY, YUAN YH, LIAO YC, HUANG RZ & SU XQ. 2013. Ecosystem carbon pools in mixed stands of hardwood species and Masson pine. Transformation of conifer monoculture into mixed conifer–hardwood plantations has been considered as an efficient management practice to sustain forest productivity. However, effects of this management practice on ecosystem carbon sequestration are still unclear. In this study, seedlings of five hardwood species (Michelia macclurei, Castanopsis fissa, Castanopsis
sclerophylla, Castanopsis kawakamii and Cyclobalanopsis myrsinaefolia) were planted separately under a Pinus massoniana (Pm) stand, and designated as Pm–Mm, Pm–Cf, Pm–Cs, Pm–Ck and Pm–Cm respectively. After 16 years of establishment, total ecosystem carbon increased by 18.0, 53.8, 25.2, 21.7 and 38.7 t ha^-1 in the Pm–Mm, Pm–Cf, Pm–Cs, Pm–Ck and Pm–Cm stands respectively compared with Pm stand. Aboveground carbon storage increased from 97.72 t ha^-1 in the Pm stand to 109.52, 131.31, 107.77, 115.76 and 123.37 t ha^-1 in the five mixed stands respectively, greatly due to an increase in hardwood tree biomass. Mineral soil carbon stock (0–60 cm) was 55.0 t ha^-1 in the Pm stand and 61.0, 72.4, 69.6, 58.6 and 66.8 t ha^-1 in the five mixtures respectively. Our results suggested that stand improvement by underplanting could be proposed as forest management option for increasing ecosystem carbon sequestration.