Estimation Study Of Forest Carbon Storage And Carbon Sequestration Potential In Shaanxi Province

Forests,as the largest carbon reservoirs in terrestrial ecosystems,play a critical role in mitigating global climate change and facilitating carbon cycling.Forest carbon storage serves as a metric for assessing the forest’s capacity to sequester carbon and its productivity,enabling the evaluation of carbon balance and providing insights into the quality of forest ecosystems.Research focused on forest carbon storage establishes a foundation for evidence-based policy-making to address climate change while also providing a theoretical framework for global studies on carbon cycling and carbon sinks.Furthermore,the study of forests’ carbon sink potential offers valuable scientific guidance for optimizing forest management,improving forest quality,enhancing ecological environments,and actively engaging in carbon cycling.Therefore,investigating the dynamic changes in forest carbon storage and carbon sink potential holds significant significance in the research on global climate change and the development of effective carbon mitigation mechanisms.This study focuses on conducting research on deciduous forests in Shaanxi Province using continuous forest inventory data.The volume-derived biomass method,in conjunction with the Google Earth Engine(GEE)platform,is employed to integrate various dominant bands,DEM,NDVI,and other index factors with fixed plot biomass.A forest biomass retrieval model for Shaanxi Province is constructed using a random forest method based on long-term time series remote sensing data.The study involves inverting the forest biomass from 1999 to 2018 in Shaanxi Province and analyzing its spatiotemporal dynamics.Furthermore,accurate estimation is conducted to assess the forest carbon storage,carbon density,and annual carbon sequestration changes in Shaanxi Province from 1999 to 2018,along with the dynamics of carbon storage and carbon density across different forest types.Additionally,the contribution of different forest types to the forest resources in Shaanxi Province is analyzed by considering factors such as age groups,origins,tree species,tree ownership,current carbon storage,and carbon density.The goal is to explore strategies for enhancing forest carbon sequestration capacity.Simultaneously,utilizing the forest inventory data from 2014 to 2018 as a reference,the average biomass density of each forest type within its age group is calculated using the continuous biomass conversion factor method.A logistic model is employed to fit the relationship between forest biomass density and age.The Markov method is utilized to forecast future forest area and allocate it proportionally to each forest type,thereby calculating its carbon sink.Finally,the study derives the carbon sink in Shaanxi Province for the next 20 years(2019-2038)and discusses the carbon sequestration potential of forests in the region.The main conclusions of this study are as follows:(1)Forest biomass in Shaanxi Province was estimated using model inversion.The sampled points in Shaanxi Province exhibited a range of forest biomass values from 0 to 90 Mg.From a temporal perspective,the forest biomass in Shaanxi Province during the periods of 1999-2003,2004-2008,2009-2013,and 2014-2018 were 305.08 Tg,340.23 Tg,393.94 Tg,and 462.28 Tg,respectively.The corresponding growth rates of forest biomass were11.52%,15.79%,and 17.35%,indicating an overall increasing trend.From a spatial standpoint,there was a notable enhancement in forest biomass across the southern region of Shaanxi(Hanzhong,Ankang,Shangluo),the central region(Xi’an,Tongchuan,Baoji,Xianyang,Weinan),and the northern region(Yulin,Yan’an).Among these,the southern region of Shaanxi(Hanzhong,Ankang,Shangluo)exhibited the most pronounced overall increase in forest biomass.(2)The forest area in Shaanxi Province during the periods of 1999-2003,2004-2008,2009-2013,and 2014-2018 was 5.0855 million ha,6.6395 million ha,6.3926 million ha,and 7.071 million ha,respectively.The corresponding carbon storage values were 152.54 Tg,170.12 Tg,196.97 Tg,and 231.14 Tg,with carbon densities of 29.99 Mg C/ha,25.62 Mg C/ha,30.81 Mg C/ha,and 32.69 Mg C/ha.The annual carbon sequestration rates were3.52 Tg C/yr,5.37 Tg C/yr,and 6.83 Tg C/yr.Overall,it can be observed that the carbon storage and annual carbon sequestration in Shaanxi Province exhibited an increasing trend from 1999 to 2018.The carbon density initially decreased and then increased,but overall,it maintained an increasing trend.(3)Overall,the forests in Shaanxi Province serve as a significant potential carbon reservoir,with varying carbon storage capacities among different age groups,origins,tree species,tree ownership,and forest types.The size of carbon storage in Shaanxi Province’s forests is influenced by various factors,as follows: Regarding age groups,middle-aged forests exhibit the highest carbon storage,while over-mature forests have the highest carbon density.Concerning origins,natural forests possess the highest carbon storage and carbon density.In terms of tree species,oak forests demonstrate the highest carbon storage,whereas Huashan pine exhibits the highest carbon density.With respect to tree ownership,state-owned forests have the highest carbon storage and carbon density.In relation to forest types,protective forests showcase the highest carbon storage,while special-use forests have the highest carbon density..(4)Enhancing the capacity of forest carbon sequestration requires attention to forest area,composition,nurturing,and management.Firstly,it is crucial to increase forest area,enhance forest coverage,and restore degraded forests.Secondly,strategic allocation of tree species,optimization of forest structure,adjustment of stand density,and promotion of sustainable forestry development models are important.Thirdly,efforts should be made to intensify forest nurturing by supporting simultaneous afforestation and nurturing,increasing forest diversity,promoting green management practices,and,if necessary,strengthening human intervention.Fourthly,a comprehensive set of measures should be implemented to promote forest management and improve forest quality.This entails establishing comprehensive institutional systems encompassing forest management and ownership,along with relevant laws and regulations.It also involves setting rational development planning goals,optimizing the development environment for forest operators,strengthening professional forestry talent development,and cultivating a highly skilled workforce.Additionally,improving forestry management approaches,innovating forest management methods,and advancing the mechanization of forestry operations are necessary steps.(5)Through Markov prediction,the forest area in Shaanxi Province is projected to reach 12.5677 million ha by 2038,with a cumulative afforestation area of 5.4967 million ha.By fitting the forest biomass density-age logistic model,the estimated cumulative carbon sequestration of newly established forests in Shaanxi Province by 2038 is 257.49 Tg C,with an average carbon density of 46.84 Mg C/ha.Assuming no significant deforestation or mortality,the forest carbon sink in Shaanxi Province is expected to reach 359.98 Tg C from2019 to 2038,representing an increase of 128.84 Tg C compared to the period of 2014-2018(231.14 Tg C).The carbon density is anticipated to continue increasing over the next 20 years,with an estimated average carbon density of 42.94 Mg C/ha by 2038.This signifies a net increase of 10.25 Mg C/ha compared to the period of 2014-2018(32.69 Mg C/ha).In terms of annual carbon sequestration,the forests in Shaanxi Province are estimated to sequester approximately 6.44 Tg C/yr.These findings highlight the significant carbon sequestration potential of the forests in Shaanxi Province.