Effects of Forest Types on SOC and DOC in the Permafrost Region of the Daxing’anling Mountains

Abstract

There is a “symbiotic relationship” between permafrost and the forest ecosystem; the melted permafrost provides sufficient water for forest growth, and the forest ecosystem plays an important role in protecting the permafrost. Aiming to study the effects of different forest types on soil organic carbon (SOC) and dissolved organic carbon (DOC) in the permafrost region of the Daxing’anling Mountains, this research focuses on the soil of the three forest types of pinus sylvestris var. mongolica forest, larch forest, and birch forest in Beiji Village, Mohe County, Daxing’anling Region, and collected vertical profile soil samples from the three soil layers of 0–10, 10–20, and 20–30 cm at three different sites types (upslope, mesoslope, and downslope) in August 2017. The results show that the forest type is the main influencing factor for the content of SOC and DOC. The site type has a significant effect on the content of SOC and DOC in the three forest types, but the difference varies slightly (p > 0.05). The content of SOC and DOC is negatively correlated with the depth of the soil layer of the vertical profile. The geodetector data analysis shows that there are significant differences (p < 0.05) among the contents of SOC and DOC in the three forest types. In conclusion, this study contributes to an in-depth understanding of carbon storage, the carbon dynamics of SOC, and the effects of different forest types on carbon balance in permafrost regions, and it provides a scientific basis for the study of the carbon cycle mechanism in permafrost regions.