Effects of mining on the carbon loss of natural forest ecosystem in mining area

Background  In the rapid development of the social economy, the demand for mineral resources is increasing. Due to large-scale and unreasonable mining activities, the mining environment was seriously damaged, resulting in a large number of abandoned land, which could not be restored in a short period. The continuous degradation of forest ecological environment, soil erosion and soil degradation lead to the significant reduction of vegetation and soil carbon storage. Therefore, artificial measures are urgently needed to restore the ecosystem affected by mining.

Methods  This paper chose the mining area of Zhuang and Miao autonomous prefecture in Wenshan of Yunnan province (the vegetation was completely destroyed) as the research object. The carbon storage of forest ecosystem under natural conditions was analyzed to measure the loss of forest carbon in mining area. Organic carbon content and storage characteristics of arbor layers (leaves, branches, trunk, bark and roots), shrub layers (leaves, roots and branches), herb layers (aboveground and underground parts), litter layers (fresh litter layer, fragmented litter layer and humified litter layer) and soil layers (0-10, 10-20, 20-30, 30-40 and 40-60 cm) were studied.

Results  1) In the vegetation layer of the mining area ecosystem, the carbon loss of the arbor layer was the main body of the vegetation layer loss (94.6%), followed by the shrub layer (3.4%), litter layer (1.1%) and herb layer (0.9%) were relatively small; 2) After mining, it also caused serious soil carbon loss. The soil organic carbon content and carbon loss in the forest ecosystem of the mining area decreased gradually with the increase of the soil layer. The soil carbon loss was mainly concentrated in the topsoil layer of 0-30 cm, accounting for 64.2% of the total soil carbon loss. 3) After mining, the total vegetation carbon loss reached 288.4 t/hm², and the total soil carbon loss reached 169.9 t/hm². Artificial mining destroyed the natural vegetation of the forest, resulting in a high amount of carbon loss in the soil layer and vegetation layer of the mining area.

Conclusions  Under the natural condition in the study area, forest ecosystems has a strong ability of carbon storage, high carbon loss happened after mining for many years. Vegetation restoration technology should be adopted to restore the ecological integrity and land productivity of the damaged land in the mining area, so as to improve the soil quality of the mining area and increase the carbon storage of the forest ecosystem.