Quantitative classification and carbon density of the forest vegetation in Luliang Mountains of China

Forests play a major role in global carbon (C) cycle, and the carbon density (CD) could reflect its ecological function of C sequestration. Study on the CD of different forest types on a community scale is crucial to characterize in depth the capacity of forest C sequestration. In this study, based on the forest inventory data of 168 field plots in the study area (E 111A degrees 30'aEuro"113A degrees 50', N 37A degrees 30'aEuro"39A degrees 40'), the forest vegetation was classified by using quantitative method (TWINSPAN); the living biomass of trees was estimated using the volume-derived method; the CD of different forest types was estimated from the biomass of their tree species; and the effects of biotic and abiotic factors on CD were studied using a multiple linear regression analysis. The results show that the forest vegetation in this region could be classified into 9 forest formations. The average CD of the 9 forest formations was 32.09 Mg ha(-1) in 2000 and 33.86 Mg ha(-1) in 2005. Form. Picea meyeri had the highest CD (56.48 Mg ha(-1)), and Form. Quercus liaotungensis + Acer mono had the lowest CD (16.14 Mg ha(-1)). Pre-mature forests and mature forests were very important stages in C sequestration among four age classes in these formations. Forest densities, average age of forest stand, and elevation had positive relationships with forest CD, while slope location had negative correlation with forest CD.