Carbon Cycling in a Mixed Deciduous Forest Floor

A study of carbon cycling within the floor of a mixed deciduous forest included estimates of litterfall, litter standing crop, root turnover, lateral root standing crop, and measurements of gaseous carbon losses from the various components. Annual carbon inputs to the system were 161 g C ° m—2 as litterfall and 733 g C ° m—2 as small roots (<0.5 cm diam). Mean annual standing pools were: 01 litter 126 g C ° m—2, 02 litter 111 g C ° m—2, small roots 340 g C ° m—2, large roots 395 g C ° m—2, and soil detritus 12,850 g C ° m—2. Annual total carbon efflux, measured in situ with an open airflow infrared gas analysis system was 1,065 g C ° m—2. Of this total, 35% was accounted for by respiration of live roots, 42.2% from root decay, 10.9% from 01 litter, and 9.7% from 02 litter. The remaining 2.2% is within the range likely associated with catabolism of root exudates and soil organic detritus. These component estimates were based on respiration rates of the individual components using a differential respirometer.