## 3 Results and Analysis  
### Spatial Distribution of Vegetation Evaluation Indicators in 2020  
The spatial distribution of FCI, annual average LAI, annual maximum FVC, and annual cumulative GPP in the Lancang-Mekong region for the year 2020 exhibited similar patterns, with higher values observed in tropical forests and lower values concentrated in nearby urban areas (Figure 3). In the year 2020, in northwestern Myanmar, western Thailand, southeastern Laos, and eastern Cambodia, the FCI exceeded 90%; however, around major cities, the FCI ranged from 10% to 30% (Figure 3a). For areas with an FCI exceeding 90% in Figure 3a, the annual average LAI, annual maximum FVC and annual cumulative GPP were greater than 4, 95%, and 2000 gC/m\({}^{2}\), respectively (Figure 3b-d). In contrast, for the areas around major cities with FCI less than 30% in Figure 3a, the annual average LAI, annual maximum FVC, and annual cumulative GPP were lower than 1, 80%, and 1500 gC/m\({}^{2}\), respectively (Figure 3b-d).  
Figure 3: Spatial distribution of vegetation evaluation indicators over the forest ecosystem in the Lancang–Mekong region in 2020. (**a**) FCI; (**b**) annual average LAI; (**c**) annual maximum FVC, and (**d**) annual cumulative GPP (gC/m\({}^{2}\)).  
In the year 2020, the overall FCI, annual average LAI, annual maximum FVC, and annual cumulative GPP in the Lancang-Mekong region for forest types were 55.73%, 3.41, 93.51%, and 2879.54 gC/m\({}^{2}\), respectively (Table 4). Myanmar had the highest forest coverage, at 65.93%, followed by Cambodia (59.88%), Laos (54.85%), Thailand (46.43%), and Vietnam (43.81%). However, Laos had the highest annual average LAI (3.99) and annual maximum FVC (95.37%) among the five countries, followed by Myanmar at 3.58 and 94.80%, Vietnam at 3.32 and 93.78%, Thailand at 3.00 and 91.16%, and Cambodia at 2.98 and 90.41%, respectively. Laos also exhibited the highest annual cumulative GPP (3093.06 gC/m\({}^{2}\)), followed by Thailand (2903.91 gC/m\({}^{2}\)), Myanmar (2845.99 gC/m\({}^{2}\)), Vietnam (2824.06 gC/m\({}^{2}\)), and Cambodia (2689.23 gC/m\({}^{2}\)). Combining the information from Figure 3 and Table 4, it can be observed that Laos, ranking third in the FCI parameter, had the highest values for annual average LAI, annual maximum FVC, and annual cumulative GPP. On the other hand, Cambodia, ranking second in the FCI parameter, showed the lowest values for three vegetation evaluation indicators.  
Figure 4 presents the spatial distribution of EQI and summary statistics of EQI for each country over the forest ecosystem in the Lancang-Mekong region in 2020. More than 48.47% of the EQI values were higher than 75 (grade I) in 2020; conversely, only 1.03% of the EQI values were lower than 35 (IV and V) around the city with an FCI below 10% (Figure 4a). The overall quality of the forest ecosystem in the Lancang-Mekong region in 2020 was better (EQI = 71.82). Among five countries in the region, Laos had the highest EQI, with a value of 76.88, followed by Myanmar and Vietnam, both with EQI values of 72.45. Thailand had an EQI of 68.79 and Cambodia had an EQI of 67.30 (Figure 4b). In general, the total of grade I (Good) and grade II (Better) combined was greater than 71%. On the other hand, the total of grade IV (Qualified) and grade V (Below standard) combined was lower than 2.5% for each country. In this, Laos stood out with the largest percentage (63.37%) of grade I (Good), showing a high level of annual average LAI, annual maximum FVC, and annual cumulative GPP, consistent with the conclusion in both Figure 3 and Table 4.