Diameter Growth Models of Picea crassifolia from Different Habitats in Qinghai Province
[Objective]The growth regularity and diameter at breast height(DBH)growth model of Picea crassifolia from different habitats were studied,which will provide empirical models and reference basis for forest protection and management.[Method]Base on the tree-ring data of Picea crassifolia in Qinghai province,the increment of tree DBH was used to analyze tree growth in different habitats.Then,five kinds of individual-tree growth models were constructed,and compared according to the model goodness of fit andindexes.Finally,origin and slope position effects were considered to develop mixed effects models,and the evaluation indices of different models were used.[Result]When trees grew to breast height,the increment of individual trees decreased with age and then changed gently.The fast-growing period of Picea crassifolia natural forests and plantations was 29-44 a and 29-39 a,respectively.The current an-nual increment of DBH(CAI)and mean annual increment of DBH(MAI)of natural Picea crassifolia were above 0.40 cm.CAI and MAI of of natural forests changed slowly,while the trees growth of plantations had relatively large variation ranges.The trend of DBH increment of Picea crassifolia were different among four slope positions.The results of optimal individual-tree growth models developed along different habitats showed that the determination coefficients(R2)were above 0.913,the total relative error(TRE)and the av-erage system error(MSE)were within±2%,the average prediction errors(MPE)were less than 5%mostly,and the average percentage standard errors(MPSE)were less than 35%.Based on the Gompertz model,the R2 of mixed effects model was 0.702,the TRE,MSE,MPE and MPSE of mixed effect model were 0.03%,-0.30%,4.23%and 29.54%,respectively,decreased by 89.3%,83.5%,20.6%and 15.1%compared with that of based model.[Conclusion]The growth patterns of Picea crassifolia are different un-der different habitats.The Picea crassifolia of natural forests have a longer vigorous growing period than that plantations.The mixed effect model of individual-tree growth of DBH considering the different habitats,can be used to estimate the changes of DBH for Picea crassifolia in Qinghai province.
diameter incrementgrowth regularityindividual-tree growth modelmixed effect modelQinghai Province
万方数据
维普
