Observed Methane Uptake and Emissions at the Ecosystem Scale and Environmental Controls in a Subtropical Forest

Land

Hui Wang¹  Jianhua Lv¹  Zhihao Liu¹  Changhui Peng¹  Hong Li²  Hong Jiang³  Xinzhang Song⁴  Quan Li⁴ 

[1] Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling 712100, China;Faculty of Architecture and Urban Planning, Chongqing University, Chongqing 400045, China;International Institute for Earth System Science, Nanjing University, Nanjing 210023, China;State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China;

关键词: CH₄ flux;    eddy covariance;    annual budget;    soil temperature;    soil moisture;   

DOI  :  10.3390/land10090975

来源: DOAJ

【 摘 要 】

Methane (CH₄) is one of the three most important greenhouse gases. To date, observations of ecosystem-scale methane (CH₄) fluxes in forests are currently lacking in the global CH₄ budget. The environmental factors controlling CH₄ flux dynamics remain poorly understood at the ecosystem scale. In this study, we used a state-of-the-art eddy covariance technique to continuously measure the CH₄ flux from 2016 to 2018 in a subtropical forest of Zhejiang Province in China, quantify the annual CH₄ budget and investigate its control factors. We found that the total annual CH₄ budget was 1.15 ± 0.28~4.79 ± 0.49 g CH₄ m⁻² year⁻¹ for 2017–2018. The daily CH₄ flux reached an emission peak of 0.145 g m⁻² d⁻¹ during winter and an uptake peak of −0.142 g m⁻² d⁻¹ in summer. During the whole study period, the studied forest region acted as a CH₄ source (78.65%) during winter and a sink (21.35%) in summer. Soil temperature had a negative relationship (p < 0.01; R² = 0.344) with CH₄ flux but had a positive relationship with soil moisture (p < 0.01; R² = 0.348). Our results showed that soil temperature and moisture were the most important factors controlling the ecosystem-scale CH₄ flux dynamics of subtropical forests in the Tianmu Mountain Nature Reserve in Zhejiang Province, China. Subtropical forest ecosystems in China acted as a net source of methane emissions from 2016 to 2018, providing positive feedback to global climate warming.

【 授权许可】

Unknown