湖南栎类天然林自稀疏边界线及影响因素研究OA北大核心CSTPCD

Self-thinning boundary line(STBL)is a curve that reflects the relationship between the maxi-mum density and factors such as the diameter at breast height and volume of the forest stand,and it is an important basis to reflect the law of stand growth and succession.In order to determine the optimal statis-tical method of STBL of oak natural forest and the main affecting factors,225 long-term monitoring sample plots of oak natural forest occurring in Hunan Province were used as research objects in the paper.The least square method,quantile regression method and random frontier method were used to fit the STBL of oak natural forest.The real stand mortality rate was used to compare and verify the three statistical meth-ods.The self-thinning state of the real stand was distinguished according to the STBL,and the site factors and forest structure factors of unsparse and sparse sample plots were analyzed.The results showed that the self-thinning curve based on quantile regression method was closer to the maximum density critical value of oak natural forest,and its fitting effect was better than those of least square method and stochastic frontier method,and the slope of oak STBL was-1.063 and the intercept was 10.232.Altitude,slope,Pielous in-dex and height-diameter ratio were significant factors affecting the self-thinning rate and starting time of oak natural forest.The STBL constructed in the paper can accurately reflect the allometric growth relation-ship between the maximum density and the average diameter of oak natural forest,and can provide a refer-ence for the study of growth succession and forest tending of oak natural forest.