Comparative analysis of forest soil carbon sink and source based on bibliometrics: Development, hotspots, and trends

Since the Industrial Revolution, massive carbon dioxide emissions from human activities have caused global warming. Forest carbon sink play a crucial role in mitigating climate change, with soil being a key component of forest ecosystem carbon pools. Both carbon source and carbon sink in forest soils have attracted significant academic interest. This paper uses bibliometrics to review and compare studies on forest soil carbon sink and source from January 1996 to April 4, 2024, divided into three stages, namely initial (1996-2004), middle (20052014), and late (2015-2024) stages. We found that publications on forest soil carbon source far exceed those on carbon sink, with a significant correlation in their trends. The United States leads in publication numbers, while the United Kingdom has greater centrality. Chinese institutions dominate in publication numbers, excelling in collaborative research. In forest soil carbon sink research, the top ten most-cited articles focus on climate change, soil respiration, and large-scale surveys. For forest soil carbon source, the focus is on climate change and soil organic matter. The research on carbon sink lags behind carbon source, and many hotspot issues remain unresolved. Over the three periods, studies on forest soil carbon sink and source have advanced in technological methods, greenhouse gases, ecosystem types, and ecosystem processes and functions. This study provides data to assist researchers in designing targeted and practical project schemes, while guiding policymakers to prioritize support for high-potential forest soil carbon projects, ultimately enhancing fund utilization efficiency.