The steady increase in atmospheric CO2 and the associated threat of global warming have resulted in a strong interest to evaluate the potential of terrestrial ecosystems, particularly forests, to serve as carbon sinks. Such evaluations require the understanding of how carbon flows and is stored within the various forest components. To this end, various research groups within Indiana University are taking very detailed measurements in various forest stands in the area (Hoosier and Morgan Monroe). The results presented in this dissertation are part of that larger research effort.

The first part deals with the organic carbon content of the two main components of the soil: the forest floor and the mineral layers. The main factor found to affect the amount of carbon stored in the soil is the availability of moisture in the soil. Vegetation age was also found to be significant after accounting for the variability in other site factors; this results in a carbon accumulation rate of 0.015 kg m-2 yr-1 in the soil.

The second part discusses the carbon, organic matter, and primary nutrient concentrations in various forest components. The various materials measured showed a lower carbon content than previous reports for other forests; this suggests that there may be an overestimation of the carbon stored in temperate forests in some previous reports. Nitrogen and potassium are the nutrients that differ the most among forest components.

The last part integrates the carbon estimations in the soil and detritus with the carbon found in the live biomass. The amount of carbon sequestered by a forest is highly dependent on stand age. Our youngest site (14 yrs.) showed a rate of carbon fixation (without mineral soil) in the order of 0.3 kg m-2 yr-1. Once the forest reaches 100 years of age, that rate drops to 18% of its initial value. Most of this carbon is sequestered in the aboveground woody components.