Z50 and Z95 root depths calculated assuming an exponential profile of root biomass.

Measured dry belowground biomass (top 1.1 m), extrapolated total root biomass (i.e., R(∞), see Methods section), dry above ground biomass, basal area, root-to-shoot ratio (R∶S, based on dry root biomass in the top 1.10 m), and depths, ZL,50 and ZL,95, of soil column containing 50% and 95% of the total root length, respectively (assuming exponential profile of linear root density). Biomass variability among plots expressed as ± standard deviation calculated for a set of 3 plot replicates at each site.