Study On Growth Characteristics Of Larix Siberian Ledb In Altai Mountains Of Xinjiang

Larix siberian Ledb is a unique species of conifer in northwestern China and one of the most widely distributed tree species in Altai mountains.In view of the special geographical location of Altai mountains in Xinjiang and the lack of relevant research,this paper used the Three issues forestry inventory data and some sample forest data in the Altai region of Xinjiang to study the growth characteristics and stand growth model of the Larix siberian Ledb forest.Not only does it make up for the lack of research related to Larix siberian Ledb in this region,but it also provides a theoretical basis for the establishment of forest management and forestry resource assessment.Through the screening and classification of inventory data,using forstat and spss23.0 analysis software,the growth characteristics of Larix siberian Ledb forest with different factors were analyzed.Then calculate the growth and growth rate of DBH under different impact factors.Then calculate the growth and growth rate of breast diameter under different influence factors.Use growth function to fit the correlation between different factors and the growth process of DBH and tree height to find the optimal growth function model.The main findings are as follows:(1)Larix siberian Ledb is mainly distributed on shady slopes and semi-shade slopes with altitudes of 1600m-2100m,and the elevations from west to east are increasing.(2)In the seven diameter classes,with the increase of diameter class,the average growth of DBH showed a trend of increasing first and then stabling(or slightly decreasing),and the average growth rate of DBH showed a gradually decreasing trend.In the same diameter class,the average growth of DBH and the average growth rate of DBH are generally represented as shady slope>half shady slope>sunny slope,and the thick soil layer is larger than the shallow soil layer,and with the increase of the elevation and the stand density,it shows the trend of increasing first and then decreasing.(3)The stand density is between 800-1000 trees per hectare,which is most conducive to the growth of stand diameter at breast height.The logarithm function model of DBH and stand density is the best,and its equation is y=-7.651n(x)+74.911(R2=0.700).There was a significant positive correlation between stands density and stands canopy density,and there was no significant correlation between understory shrubs and herb cover and height.(4)Under certain forest age,the growth of DBM in Larix siberian Ledb is mainly affected by the stand density,followed by site factors.The site conditions are the main factors that affect the growth of tree height,and the impact of stand density is not obvious.(5)Establishment of a three-variable DBH growth model of forest age,stand density index and status index And a two variable tree growth models of tree age and status index.The results are:D=-6.369+0.148 T-5.029 Z+2.060 SI(R2=0.656),H=-7.593+1.833 T+0.057 SI(R2=0.937).