Modeling carbon transfers in subtropical Chinese fir plantations: The role of stemflow and litter leachate

Abstract

Dissolved Organic Carbon (DOC) plays a crucial role in forest ecosystems by facilitating carbon turnover and enabling nutrient transfer. However, the DOC fluxes in stemflow and litter leachate are often overlooked. To address this issue, a series of simulation experiments were conducted in Chinese fir (Cunninghamia lanceolata) plantations with trees aged 5, 8, 11 and 15 years to elucidate the impact of stemflow and litter leachate on carbon flux into the soil. A quantitative relationship was established between DOC fluxes in stemflow and litter leachate, incorporating diameter at breast height (DBH) and rainfall as variables. The average DOC flux in stemflow across the four plantations was 3.82 g C m⁻² yr⁻¹, showing an increasing trend with age from 2.89 ± 1.02 to 4.43 ± 2.11 g C m⁻² yr⁻¹. The cumulative input fluxes of DOC from stemflow and litter leachate in four plantations since planting were 272, 1020, 2021 and 3470 g C m⁻², respectively. The DOC fluxes from stemflow and litter leachate in 15-year-old Chinese fir forest accounted for 0.96 % and 57.79 % of the annual net primary productivity (680.35 g C m⁻² yr⁻¹), highlighting the significant role of DOC fluxes in the carbon cycle of these ecosystems. This simulation approach effectively estimates the fluxes of DOC in stemflow and litter leachate, thereby substantially influencing assessments of carbon budgets in forest ecosystems.