Soil temperatures and active carbon components as key drivers of C stock dynamics between two different stand ages of Larix principis-rupprechtii plantation

Junyong Ma; Hairong Han; Xiaoqin Cheng

doi:10.7717/peerj.8384

Soil temperatures and active carbon components as key drivers of C stock dynamics between two different stand ages of Larix principis-rupprechtii plantation

PeerJ. 2020 Jan 21:8:e8384. doi: 10.7717/peerj.8384. eCollection 2020.

Authors

Junyong Ma¹, Hairong Han¹, Xiaoqin Cheng¹

Affiliation

¹ Key Laboratory of Ministry of Forest Cultivation and Conservation of Ministry of Education, Beijing Forestry University, Beijing, China.

Abstract

Forest soils sequester a large amount of carbon (C) and have a significant effect on the global C balance. Forests are commonly managed to maintain certain age structures but the effects of this management on soil C pools (kg C m^-2) is still uncertain. We compared 40-year-old (1GF) and 24-year-old (2GF) plantations of Larix principis-rupprechtii in North China. Specifically, we measured environmental factors (e.g., soil temperature, moisture, and pH), the active C and nitrogen (N) pools (e.g., soil organic C, soil total N, dissolved organic C and N, microbial biomass C and N), and soil processes (e.g., C mineralization and microbial activity in different seasons) in five soil layers (0-50 cm, 10 cm for each soil layer) across the growing seasons in three 25 m × 25 m plots in each age class (1GF and 2GF). Findings indicated that the soil organic C pool in the older 1GF forest (12.43 kg C m^-2) was significantly higher than 2GF forests (9.56 kg C m^-2), and that soil temperature in 1GF forests was 9.8 °C, on average, 2.9% warmer than temperature in 2GF forests. The C lost as carbon dioxide (CO₂) as a result of mineralization in the 2GF plots may partly explain the lower soil organic C pool in these younger forests; microorganisms likely drive this process.

Keywords: Environmental factors; Forest stand age; Soil carbon components; Soil organic carbon.

Grants and funding

The study was supported by the National Key Research and Development Program of China (2016YFD0600205). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.