The Forest Floor and Mineral Soil Carbon Pools of Six Different Forest Tree Species

The influence of tree species on forest soil properties has been studied for a long time. Recently, the role of soil carbon (C) pools for mitigation of greenhouse gases has highlighted the need for more knowledge on the tree species effects on soil organic C. In Turkey, the effects of six different tree species; Sessile oak (Quercus petraea), Oriental spruce (Picea orientalis), Austrian pine (Pious nigra), Turkish fir (Abies bormulleriana), Scots Pine (Pious sylvestris), and Taurus cedar (Cedrus libani) on the carbon pools of the top mineral soil (0-30 cm) and the forest floor were investigated in adjacent stands. Carbon pools of the forest floor varied from 11 Mg ha(-1) beneath the Oriental spruce to 20 Mg ha(-1) beneath the Scots pine. The C contents of the forest floor were similar among species and there was no significant difference in C mass of forest floors among species. In the 0-30 cm mineral soil layer, the highest soil organic C pool was beneath the Taurus cedar and the lowest was found in the native Sessile oak forest. Total C pools (forest floor + 30 cm mineral soil) increased in the order Quercus petraea < Abies bornmulleriana < Picea orientalis < Pious sylvestris < Pious nigra and Cedrus libani from 77 to 126 Mg ha(-1). The results suggest that tree species differ in C sequestration rates within the forest floor and mineral soil, respectively, but there is little evidence of major differences in the combined forest floor and mineral soil after five decades.