Fig. 7. Log scale plots of root length by measured diameter class (LD plot). Switchgrass photographed at 19.2 p mm^-1 with the diameter class size set at 0.052 mm; Pasture photographed at 14.3 p mm^-1, with diameter class size set tot 0.070 mm. Camera settings: ASA200, 1/23 sec, f-13, manual focus.