Summary statistics for the dataset by depth layer.

Mean and confidence interval: estimates corrected for the varying dataset (mixed regression). Minimum and maximum: median values of single years per site and depth. Regression against time: time trend with mixed regression of log transformed predictors (except pH and ANC). n = 20211 monthly samples, 47 plots, 22 years.均值与置信区间：针对异质数据集校正后的估计值（混合回归（mixed regression））。最小值与最大值：各采样点、各深度下单年度观测值的中位数。以时间为自变量的回归分析：采用对数转换后的预测变量（pH与酸中和容量（Acid Neutralizing Capacity，ANC）除外）开展混合回归得到的时间趋势。样本量：共计20211个月度样本，覆盖47个样地，观测时长为22年。