Above-ground biomass estimation of bamboo forests by integrating multi-source remote sensing and XGBoost machine learning
Accurate estimation forest biomass by remote sensing is an important basis for assessing the potential of forest carbon sinks. We explored the potential of synergistic estimation of above-ground biomass (AGB) in bamboo forests using different optical and LiDAR point cloud data,by comparing the differences between airborne multispectral and LiDAR data,respectively. In this study,the plantation forest of Acidosasa edulis,a characteristic bamboo species in Fujian Province,was used as the research object. Unmanned airborne multispectral imagery and LiDAR data were collected synchronously to extract and select the preferred feature set of a single LiDAR and multispectral imagery data each,the preferred feature set of the combined airborne LiDAR and multispectral imagery,and the combined feature set of the combination airborne LiDAR and multispectral imagery,using multivariate linear regression model (MLR) and support vector machine (SVM),random forest (RF),and eXtreme Gradient Boosting (XGBoost) to fit the bamboo forest AGB estimation model. Results showed that (1) the height and density features of LiDAR data are important for bamboo forest AGB estimation. The feature set based on multi-source heterogeneous remote sensing data was better than single data for bamboo forest AGB estimation. (2) The nonparametric model based on machine learning algorithms was better than the MLR model for bamboo forest AGB estimation;the AGB estimation model integrating XGBoost and multi-source feature set was the best fit for Acidosasa edulis bamboo,with R2 of 0.64 and Erms of 9.90 t·hm-2 . Bamboo forests have a special canopy structure,and applying LiDAR data can effectively obtain information of the vertical structure of the forest stand. Moreover,the combination of multi-sourceisomorphic data can improve the accuracy of the biomass estimation model to provide a reference for the application of the biomass survey of the fixed sample plots of bamboo forests in subtropical areas and the estimation of carbon sinks.
bambooabove-ground biomassmulti-source remote sensinglight detection and ranging(LiDAR)multispectralmachine learning