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Fig. 6. (a) Relations between root biomass density, R, and depth, z, according to Eq. [5] and [7]. For Eq. [7], values of 
i were calculated using characteristic length scale (Zr) = 0.184, R0 = 1111 g m–3, and discrete soil sample depth intervals, 
z, of 0.1 (five solid circles between the surface and z = 0.5 m), 0.5 (2 solid squares shown at z = 0.75 and 1.25 m) and 1.0 m (3 open squares shown at z = 1.5, 2.5, and 3.5 m). The data points were calculated to a depth of 4 m. The three curves were derived by least squares fitting of i and 
i to Eq. [5] using all the values calculated for a single z, and led to a single value of Zr (= 0.184), but three values of R0 including 1115, 1487, and 3092 g m–3 for z of 0.1, 0.5, and 1.0 m, respectively. (b) Same data plotted as log-linear to better illustrate the intercept shift.
