INFLUENCES OF COMMUNITY COMPOSITION ON BIOGEOCHEMISTRY OF LOBLOLLY-PINE (PINUS-TAEDA) SYSTEMS

Litterfall and decomposition processes were compared among four forest plantations that were dominated by loblolly pine (Pinus taeda L.) but that differed in terms of presence or absence of deciduous and herbac eous components. Based on aboveground litterfall, the pine-only commun ity was the most productive but had the slowest turnover of organic ma tter in the forest floor. The presence of deciduous and/or herbaceous vegetation caused more rapid turnover of forest litter and altered the nature of immobilization/mineralization patterns for N and P in the s ame material. Temporal patterns of N and P changes in the forest floor were much more dynamic in mixed pine-deciduous communities and sugges t more intense competition between microbes and vegetation for those e lements. Mineralization pulses are more frequent and occur on a differ ent temporal scale in the pine plus deciduous communities also. Result s are discussed in terms of their potential importance during ecosyste m restoration/manipulation efforts that increase or decrease the prese nce of particular vegetation components within forest communities.