Deciphering nitrogen concentrations in Metasequoia glyptostroboides : a novel approach using RGB images and machine learning  

作　　者：Cong Ma Ran Tong Nianfu Zhu Wenwen Yuan Yanji Li GGeoff Wang Tonggui Wu 

机构地区：[1]East China Coastal Forest Ecosystem Long-Term Research Station,Research Institute of Subtropical Forestry,Chinese Academy of Forestry,Hangzhou 311400,People’s Republic of China [2]Nanjing Forestry University,Nanjing 210037,People’s Republic of China [3]Department of Forestry and Environmental Conservation,Clemson University,Clemson,SC 29634-0317,USA

出　　处：《Journal of Forestry Research》2024年第6期110-120,共11页林业研究（英文版）

基　　金：supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C02053);National Natural Science Foundation of China(NSFC)(32201632).

摘　　要：Recent advances in spectral sensing techniques and machine learning(ML)methods have enabled the estimation of plant physiochemical traits.Nitrogen(N)is a primary limiting factor for terrestrial forest growth,but traditional methods for N determination are labor-intensive,time-consuming,and destructive.In this study,we present a rapid,non-destructive method to predict leaf N concentration(LNC)in Metasequoia glyptostroboides plantations under N and phosphorus(P)fertilization using ML techniques and unmanned aerial vehicle(UAV)-based RGB(red,green,blue)images.Nine spectral vegetation indices(VIs)were extracted from the RGB images.The spectral reflectance and VIs were used as input features to construct models for estimating LNC based on support vector machine,ran-dom forest(RF),and multiple linear regression,gradient boosting regression and classification and regression trees(CART).The results show that RF is the best fitting model for estimating LNC with a coefficient of determination(R2)of 0.73.Using this model,we evaluated the effects of N and P treatments on LNC and found a significant increase with N and a decrease with P.Height,diameter at breast height(DBH),and crown width of all M.glyptostroboides were analyzed by Pearson correlation with the predicted LNC.DBH was significantly correlated with LNC under N treat-ment.Our results highlight the potential of combining UAV RGB images with an ML algorithm as an efficient,scalable,and cost-effective method for LNC quantification.Future research can extend this approach to different tree species and different plant traits,paving the way for large-scale,time-efficient plant growth monitoring.

关 键 词：RGB images Random forest LNC N and P addition METASEQUOIA 

分 类 号：S791.35[农业科学—林木遗传育种]