Establishment of Stand Diameter Structure Model of Pinus sylvestris var.mongolica Plantations in Heilongjiang Province
Pinus sylvestris var.mongolica is one of the main afforestation species in northern China,which has the advantages of cold resistance,drought resistance and strong environmental adaptability.Taking Pinus sylvestris var.mongolica plantations as the research objects,the diameter distribution law of Pinus sylvestris var.mongolica plan-tations was analyzed by using the data of six fixed sample plots of different age groups in Mengjiagang Forest Farm of Jiamusi City.The relationship model between diameter class and cumulative number of plants was established,and the model was tested by various test indexes and confidence ellipse F test.The results showed as the following three aspects.(1)Under the same site conditions,the diameter of Pinus sylvestris var.mongolica plantations con-formed to the normal distribution.The number of trees near the average diameter was the largest,which gradually decreased to both sides.(2)The logistic equation can better fit the diameter distribution law,and the correlation in-dex R 2 of each plot was greater than 0.99,and the measured data were basically distributed near the fitting curve.(3)Through the F test at the significant level of 0.05,the fitting model showed no significant difference between the measured value and predicted value of the cumulative number of trees,and the fitting effect of the model was good with good rationality and applicability.
万方数据
维普
