Stem Biomass,Carbon Stock And Stand Structure Of Mongolian Scots Pine(Pinus Sylvestris Var.Mongolica) Plantation Forests Response To Climatic Factors In Horqin Sandy Land,China

Plantation forest is a possible alternative to mitigate climate change,combat desertification and land degradation in the current context of climate change.Plantation forest radial growth(Rg)should be measured and monitored to develop policies and strategies to address global climate change.In arid and semi-arid regions,global climate change significantly influences planted forest ecosystems,particularly in terms of biomass carbon and growth pattern.Mongolian Scots pine plantation forests play a significant role in ecosystem restoration and desertification mitigation in arid and semi-arid regions of China.Mongolian Scots pine is an important tree species in the"Three-North Shelterbelt Project," which aims to assist the environment and economy.However,in recent decades of global climate change,the growth and development of Mongolian Scots pine have been noticed to decline in the study area.A field survey was conducted in 2019 to take data from the study area of Zhanggutai region Horqin sandy land northeast China.Mongolian Scots pine of different health conditions based on(percentage of dead branches)such as healthy,subhealthy,stress,and shrink plantations were selected as target trees from 5 different locations.The aim of the study was to understand the role of Mongolian Scots pine plantation forests in terms of growth pattern,measurement,monitoring of biomass carbon,and growth response to climatic factors from 1965 to 2019.We measured tree diameter(DBH),height,density and collected 577 tree cores samples for analysis.Similarly,climate data was taken from the local meteorological station of Zhanggutai experimental base in Liaoning province.Furthermore,a standard allometric equation was used to determine the Mongolian Scots pine stem biomass and carbon stock.A growth pattern process,ecosystem biomass carbon,and tree-rings chronology were established to estimate the sensitivity response to climatic conditions.The results of the study are as follows:(1)As a result,this study revealed that if the range of PP<380 mm Ta<18.5 0C,VPD<0.4 kPa,and RH<55%,Mongolian Scots pine radial growth Rg,has a strong correlation with interannual precipitation PP,average air temperature Ta,water vapor pressure deficit VPD,and relative humidity RH.Meanwhile,when the required level was exceeded,negative correlations were found with tree radial growth Rg.The results further indicate that previous and existing summer PP,Ta,VPD,and RH had a positive impact on the radial growth Rg(p<0.05).The corresponding climatic variables and spatiotemporal variation quadratic relationship of average Ta,VPD,RH,and PP,R2=0.48,R2=0.52,R2=0.39,R2=0.43,were positively correlated with tree radial growth increment,respectively.(2)According to this research,Mongolian Scots pine healthy HP,sub healthy SHP,stress STP and shrink SRP,plantation stem biomass,carbon stock and stand structure response to annual precipitation PP and annual temperature Ta.The result shows the annual PP,has strong correlation with Mongolian Scots pine HP,SHP,STP,and SRP plantations carbon stock,(R2=0.87,R2=0.84,R2=0.82,R2=0.75),height,(R2=0.86,R2=0.83,R2=0.76,R2=0.71),diameter,(R2=0.82,R2=0.80,R2=0.74,R2=0.68).Meanwhile,annual average Ta,has positive correlations with carbon stock,(R2=0.86,R2=0.82,R2=0.77,R2=0.67),height,(R2=0.84,R2=0.81,R2=0.75,R2=0.61),diameter,(R2=0.81,R2=0.79,R2=0.67,R2=0.54).our results predicted that annual PP,impact on tree growth is slightly significant as compared annual Ta.However,negative correlations were found with density for both annual PP,(R2=0.41,R2=0.48,R2=0.21,R2=0.48),and annual average Ta,(R2=0.43,R2=0.32,R2=0.37,R2=0.30).To achieve fast tree growth and high stem biomass response,systematically based forest management strategies,including thinning operation and selective cuttings could be established.(3)Mongolian Scots pine has been used for vegetation restoration and windbreaks in Horqin Sandy land,Northern China,where climate change is the major factor limiting tree survival and growth.To investigate the effect of annual precipitation and annual temperature variables on stem biomass and carbon stock of Mongolian Scots pine healthy HP,sub healthy SHP,stress STP,and shrink SRP,plantation.We used a climate-sensitive allometric model to find accurate biomass with climatic factors.The result show that,stem biomass and carbon stock of Mongolian Scots pine,HP,SHP,STP and SRP plantation,have a strong correlation with annual PP,and annual Tmax,(R2=0.88,R2=0.84,R2=0.82,R2=0.61)and(R2=0.86,R2=0.82,R2=0.72,R2=0.60).While,annual average Tmini and annual Tmean,have a slightly positive correlation with the Mongolian Scots pine HP,and SHP,plantation(R2=0.73,R2=0.70)and(R2=0.76,R2=0.71).However,negative correlation(R2=0.49,R2=0.29),and(R2=0.40,R2=0.39)were found with STP,and SRP,plantation.Mongolian Scots pine,afforestation on reclamation sites brings important environmental and production benefits.Forest management guidelines are very important for fast growth.Overall,the response of Mongolian Scots pine healthy,sub-healthy,stress,and shrink plantations forests to various climatic factors were not completely consistent,indicating that healthy and sub-healthy trees responded more significantly as compared to the stress and shrink trees to climatic factors.These findings might provide a baseline for further research and studies and provide information to forest managers and policymakers for sustainable management of this plantation forests ecosystem.