Organic carbon sequestration in mineral soil layers of cold-temperate mixed forests

The aim of this study is to analyze the concentration of soil organic carbon (SOC) and C stocks in cold-temperate mixed forests in southern Québec, Canada. More specifically, the analysis deals with SOC concentrations and C stocks with respect to other key soil properties and environmental factors (such as soil pH, nitrogen, texture, structure, bulk density, litter thickness, drainage), including vegetation data (such as stems density, tree diameter and basal area). There are a total of 68 sampling sites across the various study sectors, including the collection of 109 soil mineral samples. The results indicate that SOC concentration and soil C stocks are high on average, ranging from 3.31 ±1.49 to 5.88 ±3.95% (SOC) and 70 to 114 t ha-1 C stocks, respectively. The results of the Principal Component Analysis (PCA) reveals that the texture of soils is the variable with the greatest differentiation among the sites, as well as soil acidity, nitrogen, litter thickness and topography. According to the multiple linear regression analysis, the two variables that result from the model are soil acidity (pH) and sand (%), which account for 33.2% of C stock variance.