Effect Of Climatic Factors On Stem Biomass And Stand Structure Of Larix Gmelinii And Betula Platyphylla In Daxing’ Anling Mountain,Inner Mongolia,China

Inner Mongolia Autonomous region is one of the largest forest areas in China and an important site for the protection of the environment in northern China,with 23.66 million hectares of forest,an eighth of the total area of the country,accounting for 21.03%of the forest cover.According to the results of.the fifth national monitoring of desertification in 2014,the areas of desertification and sandification cover respectively 60.9 million hectares and 40.8 million hectares.Which decrease from 0.42 million hectares to 0.34 million hectares compared to 2009.One hundred fifty nature reserves have been created in the Forest Department.24 reserves was at the national level and 48 at the level of the autonomous regions.Which consist of forest ecosystem,wetland ecosystem,desert ecosystem,wild animals and plants.It cover total area of 10.47 million hectares.During the Five-Year Plan(2011-2016),the total area of afforestation reached 1.01 million hectares,which represents one-ninth of the national areas.The reforestation of 0.41 million hectares of key areas has been completed,and over 380 projects have since been developed.Statistics also show that the entire region has completed 1.01 million hectares of afforestation and 0.16 million hectares in key areas in 2016.(1)Climate change has become a global concern for scientists worldwide,which is almost affecting every ecosystem.Larix gmelinii and Betula platyphylla are native and dominant forest species in the Daxing’anling Mountains of Inner Mongolia,playing a major role in carbon storage of this region.This study was carried out to assess the effect of climatic factors,including precipitation and temperature variables on stem biomass of Larix gmelinii and Betula platyphylla species.For this purpose,the allometric model was used for both species separately to find out accurate stem biomass along with climatic factors from 1950-2016.Total of 66 plots were randomly selected in the study area.Our study shows that,Larix gmelinii and Betula platyphylla stem biomass have a strong correlation with annual precipitation(R2=0.86,R2=0.71,R2=0.79,R2=0.59)and maximum temperature(R2=0.76,R2=0.64,R2=0.67,R2=0.52).While,annual minimum temperature(R2=0.58,R2=0.43,R2=0.55,R2=0.46)and annual mean temperature(R2=0.40,R2=0.22,R2=0.36,R2=0.19)have a relatively negative impact on stem biomass.The possible reason for that is high snow fall weather during the winter season,which slows the snow melting process affecting tree growth and biomass.Therefore,we suggest that both species have a very strong adaptive nature with a climatic variation.They can survive under dry,drought,and high-temperature stress climate conditions.(2)Forest play a major role in the regional and global carbon cycle.Climate change events have become an important issue;Forest of a different geographical region have different sensitivities to climate variation.Therefore,we examine the effect of annual precipitation and annual temperature from 1950-2016 on Betula platyphylla stem biomass and composition in Daxing’ anling Mountain Inner Mongolia China.We conduct a field survey;a total of 27 plots were taken in the research area.In this study,were used allometric equation having components of diameter at breast height(DBH)and tree height(H).Our result shows that the response of Betula platyphylla stem biomass has a strong correlation with annual precipitation(R2=0.80),and with temperature(R2=0.75).While,positive correlation were found for height with annual precipitation(R2=0.76)and annual temperature(R2=0.51).Although a negative correlation was absorbed for density with annual precipitation(R2=0.26)and annual temperature(R2=0.20).Our results also predict that competition for survival played a significant role in tree growth.To achieve fast tree growth and high stem biomass response,systematically based forest management strategy,including thinning operation and selective cuttings could be established,even under harsh Mongolian weather conditions.Our finding could suggest forest management guidelines for the normal growth of Betula platyphylla forest.