Statistics
Bivariate line-fitting of pair-wise traits across species with
contrasting life strategy (i.e. different leaf habits,
growth-forms and RGRs) was conducted with the standardized major axis
(SMA) model using the ‘smatr’ package in R (R Development Core Team,
2014). All data were first ln-transformed before line fitting.
Homogeneity among slopes and Y elevations of fitted lines were
determined referring to different groups (leaf habits and growth-forms).
Elevation homogeneity, as well as the overall slope homogeneity with 1,
were analyzed when these individual slopes of ecological groups were
homogeneous. As the absolute values of stomatal area or xylem area
should vary due to different measuring methods, we did not compare the
elevations of these regression against the one-to-one line. The impact
of RGR on these scaling relationships was defined by fitting lines of
Y/X to RGR.