Research On Biomass,Carbon Storage And Nutrient Elements Of Several Forest Types In Taihang Mountain

In order to reveal the differences in nutrient accumulation and carbon sequestration capacity of different forest types in the Taihang Mountains,Hebei,taking the Quercus variabilis-Platycladus orientalis mixed forest,Pinus tabulaeformis,Quercus variabilis and Robinia pseudoacacia in the central and southern Taihang Mountains of Hebei as the research objects.Based on the layout of standard plots,field surveys and laboratory test analysis,the biomass,nutrient content,vegetation carbon content and soil organic carbon content of different forest types were measured,and the biomass,nutrient storage,carbon storage and site conditions of the typical forest land in the area were compared.It provided a theoretical basis for the restoration and reconstruction of vegetation and the reasonable allocation of tree species in the Taihang Mountains,Hebei.The main results were as follows:(1)Among the total biomass of different forest types,Pinus tabulaeformis forest biomass was the largest,at 113.64t/hm2,and the lowest in the Robinia pseudoacacia,at 34.26 t/hm2.The biomass of the arbor layer of different forests was:Quercus variabilis forest>Pinus tabulaeformis forest>mixed forest>Robinia pseudoacacia forest.The biomass of the shrub herb layer was between 2.95～5.98 t/hm2,among them,the biomass of the shrub grass layer of the Pinus tabulaeformis forest was the largest,and the biomass of the shrub grass layer of the Quercus variabilis forest was the smallest.The biomass of different stands of litter layer had the same trend as total biomass.(2)The nutrient content of vegetation and litter layer in different forest types was shown as:total N>total K>total P.The nutrient content of different organs of arbor species was the largest in leaves and the smallest in trunks.The nutrient content of shrub grass was between 15.61～21.82 g/kg.The largest total N content was the Robinia pseudoacacia forest,and the smallest was the mixed forest.The largest total P content was the Quercus variabilis forest and the smallest was the Robinia pseudoacacia forest.The largest total K content was Robinia pseudoacacia,the smallest was Quercus variabilis.The nutrient content of the litter layer was between 12.52～18.80 g/kg.The soil nutrient content performance of each forest types:total K>total N>total P,and showed a decreasing trend with the deepening of the soil layer.(3)The soil nutrient enrichment ability of in arbor layer of different forest types was:Robinia pseudoacacia>Quercus variabilis>Pinus tabulaeformis>mixed forest.Among all the organs,leaves had the strongest enrichment ability to soil nutrients,while trunks had the weakest enrichment ability to soil nutrients.(4)The order of the nutrient storage in arbor layer of different forest types was:Quercus variabilis>Pinus tabulaeformis>mixed forest>Robinia pseudoacacia,and the overall performance of the trunk nutrient storage was the largest.The nutrient storage of shrub herb layer was the largest in Pinus tabulaeformis and the smallest in Quercus variabilis.Except for Robinia pseudoacacia forests,the litter nutrient storage of other forest types were undecomposed layer>half decomposed layer.Among the forest types,the maximum soil nutrient storage of mixed forests was 25.88 t/hm2,and the minimum of Pinus tabulaeformis was 18.60 t/hm2.The order of nutrient storage of each forest ecosystem was:Mixed forest(26.91 t/hm2)>Quercus variabilis forest(24.99 t/hm2)>Robinia pseudoacacia forest(24.90 t/hm2)>Pinus tabulaeformis forest(19.56 t/hm2).In terms of the spatial distribution of nutrient storage,the nutrient storage of the soil layer was much higher than other layers.(5)The carbon content of each organ in different forest types was between 45.16%and 64.61%,and all of them show that the roots had the lowest carbon content.The carbon content of each organ of Pinus tabulaeformis was higher than that of other forest types.The carbon content of the shrub herb layer ranges from 51.11%～53.63%,the carbon content of the underground root system ranges from 48.50%～56.03%.The largest average carbon content in the litter layer was the Pinus tabulaeformis forest:46.35%,the smallest mixed forest:38.63%.Carbon content of undecomposed layers at different levels of litter>carbon content of half decomposed layers.Among the four forest types,the average value of soil organic carbon in Robinia pseudoacacia was the largest,7.06 g/kg,and Quercus variabilis was the smallest,3.80 g/kg.With the deepening of the soil layer,the soil organic carbon of various forest types decreased.(6)Among the arbor layers of different forest types,Pinus tabulaeformis forest had the largest carbon storage,53.85 t/hm2,and the carbon storage of Robinia pseudoacacian forest was the smallest,at 10.10 t/hm2.The carbon storage of each organ was ranked as follows:trunk>root>branch>leaf.The carbon storage of the shrub herb layer was between 1.83～3.23 t/hm2.The carbon storage of litter layer was between 4.76～9.99 t/hm2.The order of soil carbon storage was:Robinia pseudoacacia forest(29.47 t/hm2)>mixed forest(21.55 t/hm2)>Pinus tabulaeformis forest(16.91 t/hm2)>Quercus variabilis forest(16.54 t/hm2).The carbon storage of each forest ecosystem was ranked as:Pinus tabulaeformis forest(83.98 t/hm2)>Quercus variabilis forest(76.74 t/hm2)>mixed forest(60.05 t/hm2)>Robinia pseudoacacia forest(46.77 t/hm2).(7)There was a very significant positive correlation between forest ecosystem carbon storage and nitrogen storage,phosphorus storage and potassium storage(P<0.01).(8)The different forest ecosystems were compared by using the membership function method.The ranking of each forest ecosystem score was:Quercus variabilis forest(0.81)>Pinus tabulaeformis forest(0.60)>mixed forest(0.47)>Robinia pseudoacacia forest(0.43).