2.7. Statistical analyses
Correlation analysis and analysis of variance were performed using SAS V8.0 statistical software (SAS Institute Inc., Cary, NC, USA). Graphing analysis was carried out with Origin 2018 software (Origin Lab, USA). Double-way ANOVA was used to analyze the effects of stand age and soil depth on soil CO2 flux, considered treatment (stand age and soil depth) as the fixed effect, replication as the random effect, and time of measurement as the repeated measure variable. Means were separated by using the least significance difference test. Correlation analysis was done to determine the relationships between soil CO2flux, SOC, temperature, and moisture when treatments and interactions were significant. Statistical significance was evaluated at P = 0.05, unless otherwise stated.