Study On Carbon Storage And Carbon Sequestration Potential Of Arbor Forests In Beijing

As the largest carbon pool in terrestrial ecosystems,forests play an important role in maintaining the global ecological balance and are the backbone of the global ecosystem.Forest carbon storage is not only an important parameter reflecting the structure and function of forest ecosystem,but also a basic parameter for evaluating forest quality and forest carbon budget.In recent years,the estimation of forest carbon reserves based on forest inventory data is mostly carried out at the national(or regional)scale,and the research on Beijing is very weak,especially the dynamic changes of forest carbon reserves in Beijing in recent years are still unclear.Using the data of the seventh(2004-2008),eighth(2009-2013)and ninth(2014-2018)continuous forest inventory in Beijing,this study used the method of biomass conversion factor continuous function to study the carbon storage and its dynamics of arbor forests in Beijing from different origins,age groups,forest species and forest types.The change was analyzed,and the DBH growth model of the main tree species(groups)in Beijing was established to predict the future carbon storage in Beijing.The main research contents are as follows:(1)The DBH growth model of the main tree species(groups)in Beijing is developed.The DBH growth of 16 main tree species(groups)in Beijing can be accurately predicted according to the location information,annual average temperature,annual average precipitation,annual average temperature difference,altitude,slope direction,slope position,soil thickness and humus thickness.In this study,the accuracy of the model is validated with 20% reserved data.Bias is between 0.166 cm and 0.532 cm,Bais% is between 1.012% and 5.119%,RMSE is between 0.881 cm and 2.939 cm,RMSE% is between 7.344% and 14.715%,and MAE is between 0.535 cm and 2.203 cm The absolute value of average relative error MRAE is between 0.084% and 11.892% between 2.203 cm.The validation results show that the overall fitting effect of the model is good,and it can effectively predict the growth of tree DBH.(2)Based on the data of Beijing Phase III Forest Resources Survey,the forest carbon reserves and carbon sinks in Beijing in the past 15 years were analyzed.From 2006 to 2016,the biomass of arbor forests in Beijing was carbon sink,which absorbed 10.30 Tg C with an average annual carbon sink of 1.03 Tg C/a.Natural forest and plantation contributed 39.81% and 60.19% of carbon sink respectively.Quercus,poplar and Pinus tabulaeformis are important contributors to forest carbon storage.The sum of the three accounts for 62.18%,56.28% and 44.20% of the total carbon storage of arbor forests in the same period,respectively.Carbon storage of young and middle-aged forests was the largest in different inventory periods,mainly because of the large area of young and middle-aged forests.The area and carbon storage of shelterbelts are the largest,accounting for 77.02%,77.22% and 75.82% of the total carbon storage of arbor forests in the same period,respectively.The area of shelterbelts accounted for 57.24%,62.43% and 75.03% of the total area of arbor forests in the same period.(3)Carbon storage of arbor forests in Beijing in the future was predicted.Based on the established DBH growth model of main tree species(groups)in Beijing,combined with the accumulation model,the continuous function method of biomass conversion factor and the carbon content of different tree species,the carbon reserves of Beijing in 2021,2026 and 2031 were predicted to be 17.09 Tg C,20.86 Tg C and 25.36 Tg C,respectively,and the interpolation method was used to predict the carbon reserves of Beijing from 2006 to 2031.The spatial distribution of carbon density is analyzed.It is found that the carbon density in Beijing has been increasing from 2006 to 2031.In 2006,the carbon density in most areas of Beijing is between 10 and 30 Mg C/hm2.By 2031,the carbon density in all areas of Beijing will be between 35 and 50 Mg C/hm2.