Abstract: This paper studied the carbon (C) storage and its distribution pattern of Pinus massoniana forest, mixed P. massoniana-broad-leaved forest, and evergreen broad-leaved forest representing three different succession stages of evergreen broad-leaved forests in Yingzuijie National Nature Reserve in Hunan Province. The C storage of the three forest ecosystems was 182.86, 179.84 and 229.12 Mg C·hm^-2, respectively. With the largest share in trunk, the carbon stored in tree layers was the main contributor to the C storage, accounting for 59.57%-67.88%, and had an increasing trend with forest succession. The carbon sequestered in soil accounted for 31.05%-36.55%, which also increased with forest succession but had a decreasing proportion with the succession. The carbon storage of understory vegetation and litters had the least share, accounting for 0.41%-3.04% and 0.65%-2.53%, respectively, and decreased with forest succession. The ratio of biomass C to soil C storage of the three forest ecosystems was 1.96, 1.69, and 2.20, respectively, and biomass C played a more and more important role in forest C sequestration during the succession from P. massoniana forest to evergreen broad-leaved forest. It was suggested that to implement near-nature forest management or simulate evergreen broad-leaved forest structure would be the main approach in promoting the carbon sequestering capacity of forest ecosystems in this region.

Key words: Spring-sown wheat, Grain quality, Growing period, Climatic conditions