Twenty-five field sampling sites were deployed in locations with undisturbed natural vegetation over the sampling period,48 taking the typical vegetation types and accessibility into consideration. Four plots ( sized) were located within each site. A total of 100 plots were sampled: 26, 21, 30, 12, and 11 for grass (GR), shrub (SH), coniferous forest (CF), coniferous and broad leaf forest (CB), and broad leaf forest (BF), respectively. The main vegetation species are: GR—Zephyranthes grandiflora, Zephyranthes candida, and Fatsia japonica; SH—Rosa chinensis Jacq, Camellia japonica L., Photinia glabra, and Thevetia peruviana; CF—Pinus thunbergii Parl., Podocarpus macrophyllus, and Pinus massoniana; and BF—Schima superba, Cinnamomum camphora, Elaeocarpus apiculatus Mast, and Sapium discolor. All plots were configured more than 30 m far away from each other to avoid overlap of the corresponding image pixels. The characteristics of vegetation on field measured sites are shown in Table 2. Tree heights were obtained by calculating the horizontal viewer-trunk distance and the viewer’s elevation angle of the tree top as measured with a tree height gauge. Tree canopy height means tree height minus canopy bottom height measured in the same way as the tree height. Radii of the tree canopy crown were measured with a laser distance detector by randomly choosing four points along the vertically projected “column” of the canopy and measuring and averaging their horizontal distances to the trunk. The fractional cover of vegetation (VFC) was measured using the photography method suggested by Gu et al.49 The precise locations of the plots were determined within an error of 1 m using a Starlink Invicta™ 210 Global Positioning System (GPS) receiver (RAVEN Industries, Inc., USA). LAI measurements were taken in early May 2010 under diffuse radiation conditions of overcast sky. The two-year difference between field and satellite data was addressed by carefully selecting plots with no change to vegetation type and coverage within that period. Two LAI-2000 Plant Canopy Analyzers (Li-COR, Lincoln, Nebraska) were operated in remote data acquisition mode, one used for reference readings (sky) and positioned in an open area proximal to the sampling site, and the other used in each plot to measure light transmission through the canopy. The under-canopy measurements were taken at about a 1 m height for forests and on the ground for shrubs and grasses. Both LAI analyzers were covered with a 270-deg view cap. About 5 to 8 below-canopy measurements were taken every 2 to 3 m along two parallel transects spaced by 10 m. The below-canopy measurements were compared with the above-canopy readings and the LAI was calculated and averaged for each plot.