Least squares approximations 3 Partial least square regression 2 Partial least squares regression (PLSR) 2 Agriculture 1 Chromium 1 Chromium concentration 1 Decision trees 1 Economic and social effects 1 Environmental economics 1 Equivalent water thickness 1 Explanatory variables 1 Forecasting 1 Gradient boosting 1 Gradient boosting decision tree 1 Gradient boosting decision tree (GBDT) 1 Health risks 1 Heavy metals 1 Hieracium umbellatum 1 Hyperspectral models 1 Hyperspectral remote sensing technology 1 Independent variables 1 Intraspecific trait variation 1 Leaf dry matter 1 Leaf dry matter content 1 Leaf mass per area 1 Leaf water content 1 Linear regression 1 Mean square error 1 Nonlinear systems 1 Optimal principal component 1