Abstract:

According to Forest Resource Inventigation Data from Fuzhou,by using the simultaneous equations method of nonlinear error measurement,the simultaneous equations of diameter growth models and height-diameter curve of five empirical growth models were established.Root mean square error(RMSE)、mean absolute deviation(MAD)、Coefficient of determination(R²) and prediction accuracy were selected to be the model evaluation indicators for comparing the fitting effect of five models.The results showed the fitting accuracy of the five models were all greater than 90% and the Logistic model was the optimal model,the prediction accuracy of diameter-age curve and height-diameter curve were 92.85% and 95.15% respectively.After paired t-test,there was no significant difference between measured and predicted values of average DBH and average height,with fair fitting effect.Analysis data shows that the rapid growth period of DBH of Castanopsis carlesii stand lags behind the rapid growth period of tree height and they are all in the young and middle-aged forest period,then the growth rate gradually slows down.The model can be used to describe the growth law of Castanopsis carlesii forest in Fuzhou,optimize the model structure,reduce the influence of errors on the prediction results,and establish the compatibility and consistency among DBH,tree height and age of forest,which provides reference for Castanopsis carlesii forest growth prediction.

Key words: Castanopsis carlesii, Height-diameter cueve empircial growth model, Error measurement model