A Decrease in Oak Litter Mass Changes Nutrient Dynamics in the Litter Layer of a Central Hardwood Forest

Abstract

The abundance of oak is declining in the central hardwood forest, resulting in structural and functional changes in the litter layer. We hypothesized that a decline in oak litter mass associated with a lower oak component will result in an increase in nutrient cycling rates in the litter layer. To test this hypothesis, we compared mass loss and C, N, P, and Ca dynamics in pure oak litter and in litter made of 48% oak plus 52% five other deciduous species in a central hardwood forest in West Virginia. In 12 months of litter decomposition, pure oak litter decomposed more slowly, retained more C and N, immobilized more and subsequently did not release P, and released less Ca than litter consisting of 48% oak plus five other species. Annual stand-level nutrient fluxes in pure oak and in 48% oak plus five other species litter were correspondingly 4.1 and 4.4 kg ha 1 N, 0.22 and 0.17 kg ha 1 P, and 9.3 and 16.7 kg ha 1 Ca. These results indicate that a decline in oak will cause more rapid nutrient cycling in the litter layer of affected central hardwood stands.