The Study Of Crown Width Growth Models And Height To Crown Base Growth Model For Pinus Massoniana And Liquidambaris Formosana In Mixed Planta

As an important part of trees,the size of crown width and height to crown plays an important role in the growth of trees,so it is of great significance for predicting crown width and height to crown.Based on the mixed ratios of Pinus massoniana and Liquidambar formosana incense mixed forest in Yedonghe Town,Huangping County,Guizhou Province(7:3,5:5 and 3:7 for Pinus massoniana:Liquidambar formosana incense),1771 Pinus massoniana and 1602 Liquidambar formosana trees in 55 standard plots of land were constructed,and the crown width models,the height to crown models and height base models of Pinus massoniana and Liquidambar formosana were constructed,respectively.By analyzing the variation rules of crown width,height to crown and tree height of Pinus massoniana and Liquidambar formosana in different mixed forest stands and their relationship with the competing factors of trees,the mixed ratio and tree species were used as dumb variables,and other stand variables were added to construct generalized models of crown width,height to crown and tree height of Pinus massoniana and Liquidambar formosana,respectively.Based on the generalized crown amplitude models of Pinus massoniana and Liquidambar formosana,a hybrid model and quantile crown amplitude prediction model of Pinus massoniana and Pinus massoniana were constructed,respectively.Based on the height to crown generalized model and tree height generalized model of Pinus massoniana and Liquidambar formosana,the height to crown compatibility model of Pinus massoniana and Pinus massoniana was constructed by simultaneous equations,and the constructed model was evaluated.The results of the study showed that:(1)The crown amplitude of Pinus massoniana and Liquidambar formosana was positively correlated with distance-independent competitive factors(HDH and DDH).The different mixing ratios showed significant differences in the height to crown and tree height of Pinus massoniana and Liquidambar formosana.(2)The coefficients of determination of the crown width base model of Pinus massoniana and Liquidambar formosana were 0.4231 and 0.4832,respectively,and the coefficients of the crown width generalized model of Pinus massoniana and Liquidambar formosana after adding tree variables and stand variables were 0.4810 and 0.5582,respectively.(3)Based on the generalized model of crown width of Pinus massoniana and Liquidambar formosana,a mixed model and a quantile combination model were constructed respectively,and the root mean square error of the model was compared,and the prediction effect of the mixed model on crown amplitude was better.(4)The coefficients of determination R2 were 0.6019 and 0.6333 for the height to crown dumb variable model containing the mixed ratio Zi were 0.6019 and 0.6333,respectively,and the R2 for the height to crown generalized model of Pinus massoniana and Liquidambar formosana with the high diameter ratio(HD)and the fault area per hectare(G),respectively,and the R2 for the tree height dumb variable model for Pinus massoniana and Liquidambar formosana containing the mixed ratio Zi,respectively The R2 of the tree height generalized models of Pinus massoniana and Liquidambar formosana after adding stand density(N)and fault area per hectare(G)were 0.6810 and 0.7776,respectively.The compatible the height to crown models of Pinus massoniana and Liquidambar formosana are constructed based on the generalized model of the height to crown and tree height,respectively,in which the R2 of the height to crown t model of Pinus massoniana is 0.6612,the R2 of the tree height model is 0.6789,the R2 of the height to crown model of Liquidambar formosana is 0.6900,and the R2 of the tree height model is 0.7768.