Study On Carbon Sequestraition Rate And Potential Of Typical Forests In Shaanxi

The study aims to estimate carbon sequestration rate and potential of typical forests in Shaanxi, through field investigation, laboratory analysis and data processing analysis. We established coupled relationships between cabon pools of arbor layer and undergrowth vegetation layer, vegetation layer and litter layer, aboveground layer and soil layer in major forest ecosystems in Shaanxi. Besides, we explored their carbon sequestration potentials initialily.The main results were as follows.(1) The average carbon sequestration rates of the young forest, middle-aged forest and near-mature forest were 3.06, 5.59 and 2.09 t·hm-2·a-1, respectively. The average carbon sequestration rates of vegetation layer, litter layer and soil layer were 3.38, 0.18 and 0.06 t·hm-2·a-1, respectively. The carbon sequestration rate of soil layer was lower than vegetation layer and litter layer, which had a strong carbon sequestration capacity and were the main contributors to carbon sequestration of forest ecosystems. The average carbon sequestration rates of major forest types in Shaanxi manifested as: Populus spp(11.32 t·hm-2·a-1) > P.armandii et al(4.59 t·hm-2·a-1) > Quercus acutissima Carruth et al(2.88 t·hm-2·a-1) > Quercus variabilis(2.52 t·hm-2·a-1) > Pinus tabulaefomis(2.49 t·hm-2·a-1) > Robinia pseudoacacia(2.44 t·hm-2·a-1) > Quercus liaotungensis(2.00 t·hm-2·a-1) > Betula spp(1.65 t·hm-2·a-1), Broad-leaf forest(3.72 t·hm-2·a-1) > Coniferous forest(3.48 t·hm-2·a-1).(2) The average carbon sequestration potentials of the young forest, middle-aged forest and near-mature forest were 149.37, 110.61 and 86.42 t·hm-2, respectively. The carbon sequestration potential decreased gradually as stand age increased. The carbon sequestration potentials of the vegetation layer and the soil layer were 59.63 and 54.17 t·hm-2, accounted for 50.8% and 46.1% of that of the entire forest ecosystem. The carbon sequestration potential of major forest types in Shaanxi manifested as: Populus spp(216.91 t·hm-2) > Quercus variabilis(139.04 t·hm-2) > P.armandii et al(107.11 t·hm-2) > Quercus liaotungensis(102.10 t·hm-2) > Betula spp(96.94 t·hm-2) > Quercus acutissima Carruth et al(95.54 t·hm-2) > Robinia pseudoacacia(92.50 t·hm-2) > Pinus tabulaefomis(89.37 t·hm-2).(3)The carbon sequestraition capacities of the near-mature forest was lower than that of the young forest and the middle-aged forest, but its carbon sequestrationcapacity cannot be ignored. In order to enhance the ability to sequester carbon, we should strengthen the management of the near-mature forests, such as harvest reasonably. The carbon sequestration rate of the vegetation layer was higher than that of the litter layer and the soil layer significantly. Meanwhile, the carbon sequestration potential of the vegetation layer was higher than that of the litter layer respectively. The carbon sequestration capacity of the vegetation layer was the strongest among different forest ecosystem layers.