A study on the carbon density of forest soil in the north of Yanshan Mountain

The changes in content of soil organic carbon were analysed and soil thickness,volume weight and soil organic carbon content of five forest types in the north of Yanshan Mountain were determined.The results showed that there was significant difference in soil organic carbon content from 0 cm to 40 cm soil layer,it could be used as an important index for measuring soil carbon;The soil carbon density in different types of forests could be arranged from high to low as Populus davidiana Larix principis-rupprechtii Betula puatyphlla Quercus mongolica Pinus tabulaeformis.The soil carbon density of plantations was 11% less than natural forests.The carbon density of brown soil,cinnamon soil,meadow soil and aeolian sand were 162.944 5t/hm2,103.040 7t/hm2,298.019 8t/hm2 and 98.809 6t/hm2 respectively.