Fig. 6

Regression diagnostics plots based on four modeling methods. a Multiple linear regression model. b Support vector machine model. c Artificial neural network model. d Random forest model. The horizontal axis represents the predicted AGB obtained from the model, and the vertical axis represents the AGB measured manually at ground level. Marginal rugs in the residuals-analysis plot were used to visualize the distribution of data on each axis. The solid cyan line represents a 1:1 relationship. In the training set, the four models tended to underestimate the AGB, whereas in the test set they tended to overestimate the AGB