Predicting SOC Concentrations in a Subtropical Mixed Secondary Forest Using Hemispherical Photography

In order to detect the relations of canopy structure to surface soil organic carbon (SOC) concentrations, we carried out plant census, acquisition of hemispherical photographs and soil sampling in a secondary broadleaved forest in Deqing Sanchading Nature Reserve, Guangdong, China. SOC concentrations did not exhibit significant difference among the 5 plot groupings, though stand structure represented by mean tree height and mean diameter at breast height (DBH) had significant difference. Regression analysis indicated that a significant positive correlation existed between SOC concentration and leaf area index (LAI), while a significant negative correlation was found between SOC concentration and canopy openness (CO), direct transmitted gap light (TransDir), and diffuse transmitted gap light (TransDif), respectively. Findings from this study have implications for enhancing carbon sequestration by better management of forest and the results suggest that hemispherical photography can serve as a good means for predicting surface SOC concentrations under a forest canopy.