350 



REICHLE, DINGER, EDWARDS, HARRIS, AND SOLLINS 



F M 



1972 



Fig. 1 Seasonal dynamics of lateral root carbon in the Liriodendron forest for 

 the period April 1971 to March 1972. Net carbon accumulation (calculated by 

 difference) equals 290 g/m 2 , and root-carbon turnover (calculated by 

 difference) amounted to 360 g/m 2 through March. A conversion factor of 

 0.387 was used to convert root organic matter to carbon. The smaller 

 conversion factor reflects the greater ash content of underground material. 

 Mean annual standing crop of lateral root carbon is 650 g C/m 2 . 



of 2 (38.7%), giving a mean annual value for litter of 237 g C/m 2 . r4o seasonal 

 pattern of carbon concentration in litter was discernible. The total amount of 

 Oi litter carbon showed a decrease during the summer and an increase in the 

 fall, whereas 2 litter carbon increased gradually during summer and fall. 



Soil organic matter decreased from 4.65% in the upper 10 cm to 1.25% at 

 the 21- to 30-cm depth (Table 3). The total amount of carbon was calculated, 

 assuming 58% carbon (Jackson, 1958), to be 12.3 kg C/m 2 to a depth of 75 cm. 



Heterotrophic Carbon Pool 



Calculations of canopy arthropod biomass were based upon weekly 

 measurements of population densities per leaf and converted to unit area 

 biomass using litterfall estimates of the number of leaves per square meter 

 (Reichle and Crossley, 1967). Total biomass of herbivores averaged 243 mg (dry 

 weight)/m 2 during the growing season, and predaceous arthropods averaged 61 

 mg/m 2 (Fig. 3). The numbers of leaf-feeding herbivores (geometrids; tree 



