鸡公山自然保护区杉木人工林树高-胸径模型研究OA北大核心

[Objective]Cunninghamia lanceolata is a typical subtropical tree species and Jigongshan nature reserve is the northern edge of its distribution.The relationship between its diameter at breast height and tree height was explored and a suitable height-D model was constructed to provide a certain reference basis for its tree growth and the adaptive forest management.[Method]Taking the Cunning-hamia lanceolata plantation in the Jigongshan National Nature Reserve as the research object,27 com-monly used height-D empirical models were selected and 5 optimal basic models were screened using the five model evaluation indices,namely,adjusted coefficient of determination(R2adj),root mean square error(J),mean absolute error(Q),relative mean absolute error(R)and Akaike information criterion(A).15 modified models were constructed by using correlation analysis to determine the cor-relation between the first live branch height(Z),crown width(W)and tree height(H)and then intro-ducing them into the selected basic models.The differences in fitting effects among modified models were analyzed to determine the appropriate height-D model.[Result]27 height-D empirical models can be solved.The fitting effects of M-10,M-16,M-17,M-22 and M-25 have better fitting effects.Taking into account the fitting and validation effects of the models,the fitting effect of M-10 among the basic models and M-16 with Z(M-16_Z)among the modified models are both the best,and comparing to these two models,the fitting effect has increased from 0.667 1(M-10)to 0.742 6(M-16_Z).[Con-clusion]Hence,the suitability of the model may be influenced by the factors such as the location and type of the stand.The modified model M-16 with Z is suitable for quantifying the relationship between tree height and diameter at breast height of Cunninghamia lanceolata plantation in Jigongshan nature reserve.