Proportion of living biomass in the total dry mass of belowground organs of various plant communities

Proportion of living belowground plant biomass estimated for various types of meadows, grass stands of clear-cut areas, sedge stands of wetlands and for Cuban savannas and forests is reviewed. Analysis was done using a staining technique and laborious visual separation of living belowground biomass from soil cores and blocks. The differences in the amount of living belowground plant biomass are mostly associated with the type of plant community. The highest amounts of living belowground biomass (1100 to 2300 g.m-2) were recorded most frequently in the unmown moist meadow stands (percentage of living belowground biomass was over 60%) and in mountain grass stands of clear-cut sites (66-95%). A lower percentage and amount of living biomass was found in the driest habitat (23%, 860 g.m-2) and in several wetlands (10-13%, about 500 g.m-2 or less). Mown meadows were characterized by a lower percentage of living belowground biomass and lower dry mass of total and living belowground plant parts. Living belowground biomass of 433 and 517 g.m-2 (34 and 50%) was recorded in natural savannas, while 745 (74%), and 512 to 1122 g.m-2 (39-65%) was recorded, respectively, in the anthropogenic savanna stands dominated by Axonopus compressus and Paspalum notatum. The percentage of living fine roots in the total dry mass of fine roots of Cuban forests varies considerably: 41 and 47% (554-758 g.m-2) in mangrove forests, 30 and 56% (64-90 g.m-2) in evergreen broad-leaved mountain forests and 23 and 49% (87-200 g.m-2) in semideciduous lowland forests. Both the proportion of living plant organs in total belowground dry mass and the amount of belowground plant necromass vary greatly, which may reflect differences in root mortality and the decomposition rate of dead belowground plant parts associated with various habitat conditions.