Abstract:

In this paper, the carbon storage and spatial distribution in young stands with four vegetation restoration patterns were investigated in Karsts area, Guizhou Province. The four vegetation restoration patterns included Sorbus pohuashanensis forests, Znthoxylum bungeanumi forests, Cupressus funebris forests, and Dodonaea viscose forests. The results showed that carbon concentrations varied with different tree organs in the same tree species and varied with different tree species in the same tree organ as well. Carbon concentrations were higher in aboveground organs than that in underground organ for all studied tree species except Sorbus pohuashanensis. Variation coefficients of carbon concentrations ranged from 0.88% to 7.02% for different organs of different tree species. Carbon contents ranged from 309.7 to 461.0, 335.4 to 569.6, 307.0 to 400.9 g·kg^-1 in shrub, herb, and litterfall layers, respectively. Mean organic carbon contents ranged from 30.238 to 57.243 g·kg^-1 in soils (0~10 cm depth). At the early stage of vegetation restoration, soil organic carbon content increased 56.4% and 33.5% in Cupressus funebris forests and Sorbus pohuashanensis forests, but decreased 2.1% in Zanthoxylum bungeanum forests when compared with pre-converted farmland. Soil organic carbon content gradually decreased with increasing soil depth. Soil carbon storages (0~20cm depth) were 113.1, 82.4 and 126.8 t·hm^-2 in Sorbus pohuashanensis , Zanthoxylum bungeanum, and Cupressus funebris forests, respectively. Soil carbon storage was increased by 31.1% and 47.1% in Sorbus pohuashanensis and Cupressus funebris forests, but decreased 4.4% in Zanthoxylum bungeanum forests compared with pre-converted farmland. Carbon storage in soils (0~10 cm depth) was 50.5 t·hm^-2 in Dodonaea viscose forests, The carbon storages were 117.2, 84.1, 127.9 and 53.7 t·hm^-2 in Sorbus pohuashanensis, Zanthoxylum bungeanum, Cupressus funebris and Dodonaea viscose forest ecosystems, respectively. Carbon stocks in different components of the studied forest ecosystems were in an order as: soil>vegetation>litterfall. Sorbus pohuashanensis forests had the highest capacity of carbon sequestration and was up to 1.2 t·hm^-2a^-1; Dodonaea viscose forest was the next (0.7 t·hm^-2a^-1) and Cupressus funebris forests was the lowest (0.08 t·hm^-2a^-1) in the four vegetation restoration patterns.

Key words: Karsts area, vegetation restoration, carbon content, carbon storage, Guizhou Province