The Study Of Natural Secondary Forest And Its Artificial Regeneration Forests On Ecosystem Carbon Storage, Rainy Area Of West China

Under the background of global climate changing, the effects of forest management to retard atmospheric CO2 rising had been studied widely. The forest regeneration which is an important part of forest management is one of the key factors to impact the forest vegetation and soil carbon storage. This paper systematically studied on the ecosystem carbon storage which included vegetation carbon storage, soil carbon storage, litter carbon storage and the soil active carbon pool under natural secondary forest and its artificial regeneration forests, which formed by Oreocnide frutescens plantation, Symplocos laurina plantation and Cunninghamia lanceolata plantation. The results as follows:(1) The results showed that the mean carbon content of all organs were 48.87%、 50.46%、50.59% and 48.05% for the tree species Lithocarpus glaber, Oreocnide frutescens, Symplocos laurina and Cunninghamia lanceolata respectively. Carbon content ranged from 42.57% to 49.12% and 45.53% to 49.59% in living-understory layer and litter fall layer, respectively within the four vegetation types. The mean carbon content of soil of the four vegetation types were 8.67 to 14.83 g·kg-1. Compared with the natural secondary forest, the carbon content of three artificial plantations reduced 14.1%,27.2% and 41.5%.(2)The vegetation layer carbon storage of four vegetation were between 32.53 to 57.12 tC·hm-2. Compared with the natural secondary forest, the vegetation layer carbon storage of three artificial plantations increased 30.9% to 70.9%. The tree layer carbon storage increased 60.4%-104.3%, but the Shrub and herb layer carbon storage reduced 48.1%-77.0%. Among the three artificial plantations, the amount of tree layer carbon storage was Oreocnide frutescens plantation(53.94tC-hm-2)>Symplocos laurina plantation(44.96tC-hm-2)>Cunninghamia lanceolata plantation(42.34 tC-hm-2). The amount of Shrub and herb layer carbon storage was Oreocnide frutescens plantation> Cunninghamia lanceolata plantation> Symplocos laurina plantation.(3) The amount of litter layer carbon storage is between 0.17 to 1.21 tC·hm-2.The litter carbon storage of natural secondary forest reduced significantly after updated (p<0.05). Compared with the natural secondary forest, the litter layer carbon storage of three artificial plantations reduced 54.5%-86.0%. Among the three artificial plantations, Oreocnide frutescens plantation had higher litter layer carbon storage than Cunninghamia lanceolata plantation and Symplocos laurina plantation.(4) The amount of soil layer carbon storage is between 94.23 to 137.32 t C-hm’2.The soil carbon storage of natural secondary forest reduced significantly after updated (p<0.05). Among the three artificial plantations, the soil carbon storage of Cunninghamia lanceolata plantation(94.23tC·hm-2) was lower than Oreocnide frutescens plantation(116.56tC·hm-2) and Symplocos laurina plantation(124.23 tC·hm-2).(5) The result showed that the ecological system carbon storage of four vegetation types were between 138.40 to 171.06tC·hm-2.The ecological system carbon storage of natural secondary forest also changed after updated. Compared with the natural secondary forest, the ecological system carbon storage of Oreocnide frutescens plantation increased 3.17tC·hm-2, but Symplocos laurina plantation and Cunninghamia lanceolata plantation reduced 0.33tC·hm-2 and 32.66tC·hm-2.(6) The soil microbial biomass carbon, ease of oxidation of carbon and Soil water-soluble organic carbon of four vegetation types were 133.93 to 364.79mgC·kg-1, 46.64 to 188.67mgC·kg-1 and 0.81 to 2.31 gC·kg-1.The amount of soil microbial biomass carbon, ease of oxidation of carbon and Soil water-soluble organic carbon reduced significantly after natural secondary forest updated(p<0.05). Compared with the natural secondary forest, the amount of microbial biomass carbon of 0-40cm layer reduced 34.5%-39.8%, the amount of ease of oxidation of carbon reduced 8.4%-23.9%, and the amount of Soil water-soluble organic carbon reduced 13.8%-41.2%. Among the three artificial plantations, the amount of soil microbial biomass carbon and ease of oxidation of carbon were Oreocnide frutescens plantation> Symplocos laurina plantation> Cunninghamia lanceolata plantation. The amount of soil ease of oxidation of carbon was Oreocnide frutescens plantation> Cunninghamia lanceolata plantation> Symplocos laurina plantation. It suggests that human disturbance impacted significantly the amount of soil activated carbon of secondary forest in the process of updating.