Relationship between stemflow (SF, % of total precipitation) and age (in years) for deciduous (“Decid”) and evergreen (“Everg”) tree species. Points are grouped by intervals of 15 successive age values, and the y -axis presents percentiles of the SF values of these groups based on a normal approximation (median and 95% confidence interval, cf. Harrell, 2001), placed at the median group values for age on the x -axis.