Abstract:

To provide potential implications of species selection for carbon plantation, differences in carbon sequestration pattern and net ecosystem production (NEP) were determined between two 36-year-old plantations of broadleaved species, Castanopsis kawakamii and Cunninghamia lanceolata, in Sanming, Fujian. Annual net carbon sequestration was 13.639 and 6.599 t C·hm^-2a^-1, respectively, in the C. kawakamii and the C. lanceolata, among which the annual biomass increment and the litterfall production was evenly distributed. To the annual net carbon sequestration, the contribution of stem (wood plus bark) increment was much lower, and that of branch increment was much higher in the C. kawakamii than in the C. lanceolata (26.6% versus 40.3%, and 11.5% versus 0.3%). In both plantation, the above and belowground litterfall accounted 60% and 40% respectively for the annual litterfall production, which was estimated 7.183 t C·hm^-2a^-1 in the C. kawakamii and 3.554 t C·hm^-2a^-1 in the C. lanceolata. Annual soil heterotrophic respiration was responsible for a C loss of 5.983 and 2.984 t·hm^-2a^-1 from soil to atmosphere in the C. kawakamii and the C. lanceolata, respectively. Carbon balance analysis showed there were a positive net ecosystem production (C sink), 7.656 and 3.615 t C·hm^-2a^-1 , for the C. kawakamii and the C. lanceolata, respectively. For the purpose of carbon management, C. kawakamii might be a more suitable species than C. lanceolata in local region.

Key words: Castanopsis kawakamii, Cunninghamia lanceolata, carbon sequestration, carbon balance