Soil‐atmosphere exchange of greenhouse gases from typical subalpine forests on the eastern Qinghai‐Tibetan Plateau: Effects of forest regeneration patterns

Abstract Forest regeneration plays an important role in the carbon (C) and nitrogen (N) budget after clear‐cutting. Nonetheless, the effects of regeneration pattern on soil‐atmosphere exchange of greenhouse gases (GHG; CO 2 , CH 4 and N 2 O) remain poorly understood on the eastern Qinghai‐Tibetan Plateau. This study reports measured field layer GHG fluxes from Picea asperata broadleaved mixed forest (MF, mixed forests with planted P. asperata and natural regeneration of broadleaved species), natural secondary forest (NF, natural without assisted regeneration), and P. asperata plantation forest (PF, artificial planting) to investigate the influence of regeneration patterns on soil GHG fluxes. The soils of the three forest types acted as CO 2 and N 2 O sources and CH 4 sinks. The seasonal variation in GHG fluxes was related to soil temperature, rather than soil moisture. Forest types originating from different regeneration processes exhibited different gaseous C fluxes (CO 2 and CH 4 ), but did not exhibit significant effect on N 2 O emissions. NF and MF had higher CO 2 emissions than PF. The difference was related to soil C and N density, NH 4 + concentration, and soil β‐glucosidase activity, rather than the soil microbial community. NF had higher CH 4 uptake than the other two forest types, which is possibly related to specific individual phospholipid fatty acids. Overall, forest types differing in regeneration patterns had a significant impact on the C balance from the perspective of soil‐atmosphere exchange of gaseous C at our site. Therefore, the GHG fluxes should be considered when taking measures of forest management and regeneration practices in this region.