## 3 Results
### The Temporal and Spatial Variation Trends of LUCC Since 1990  
The spatiotemporal characteristics of LUCC were presented using a conversion matrix by areas. The TPs in the ZXEB are shown in Tables 2-5, the map of this conversion process is projected in  
Figure 4: Map of the net change in six land-use types from 1990 to 2000 and 2000 to 2017. Figure 3: Net change in land-use and land-cover from 1990 to 2017. (**a**) 1990–2000. (**b**) 2000–2017. Figure 5. During both periods, unused land was the smallest land-use type (less than 0.01% of total area), so this class was not analyzed. During 1990-2000, the TPs of all the land-use types were kept relatively stable and were larger than 0.95. However, TPs indicated that woodland was the most stable land-use type with 0.9973 TPs. Woodland was also the dominant land-use type (63% of total area) having experienced both gain and loss processes; a total of 522 km\({}^{2}\) of woodland was increased and then 286 km\({}^{2}\) decreased (Table 2). The most obvious woodland increase occurred in the middle cities Guigang, Laibin, and Nanning (Figure 5a). The most dynamic classes were grassland with TPs of 0.9564, followed by cropland and water bodies with TPs of 0.9672 and 0.9741 (Table 3), respectively. Approximately 527 km\({}^{2}\) of grassland was converted into other land-use types, mostly woodland (470 km\({}^{2}\)). Meanwhile, a total of 123 km\({}^{2}\) of grassland was converted from other land-use types. The most obvious losses in grassland occurred in Guiang, Laibin, Wuzhou, and Nanning. Cropland decreased by about 992 km\({}^{2}\). Most of it turned into water bodies and built-up land, and the most obvious cropland losses occurred in Guangdong province (Guangzhou, Foshan, and Zhaoqing). The size of water bodies increased dramatically during this period, predominantly as a result of conversion from cropland, and mainly in the eastern cities (Zhaoqing, Foshan, and Guangzhou). Built-up land experienced the most obvious increase (648 km\({}^{2}\)) during this period, most significantly in Guangdong province (Guangzhou and Foshan) (Figure 5b). There was no loss of built-up land during this period. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & **Cropland** & **Woodland** & **Grassland** & **Water Body** & **Built-Up Land** & **Unused Land** & **Losses** \\ \hline \multirow{8}{*}{2000–2007} & Cropland & 37,526.41 & 157.99 & 12.86 & 131.98 & 1296.82 & 0.82 & 1600.46 \\  & Woodland & 81.47 & 103,935.64 & 293.33 & 48.21 & 526.45 & 3.01 & 952.48 \\ \cline{1-1}  & Grassland & 4.26 & 248.41 & 11,345.65 & 17.23 & 84.78 & 0.04 & 354.73 \\ \cline{1-1}  & Water body & 33.94 & 6.95 & 36.22 & 3901.20 & 266.68 & 1.89 & 345.68 \\ \cline{1-1}  & Built-up land & 0.00 & 0.00 & 0.00 & 0.00 & 4578.57 & 0.00 & 0.00 \\ \cline{1-1}  & Unused land & 0.02 & 0.42 & 0.02 & 0.42 & 1.55 & 22.16 & 2.43 \\ \cline{1-1}  & Gains & 119.70 & 413.77 & 342.42 & 197.85 & 2176.28 & 5.77 & 3255.78 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The LUCC matrix in the ZXEB from 2000 to 2017 (units: km\({}^{2}\)). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & **Cropland** & **Woodland** & **Grassland** & **Water Body** & **Built-Up Land** & **Unused Land** & **Losses** \\ \hline \multirow{8}{*}{1990–2000} & Cropland & 38,936.19 & 49.77 & 3.27 & 396.47 & 542.02 & 0.01 & 991.54 \\  & Woodland & 92.23 & 104,364.36 & 119.25 & 20.78 & 53.29 & 0.00 & 285.55 \\ \cline{1-1}  & Grassland & 42.73 & 470.11 & 11,577.32 & 5.15 & 9.19 & 0.00 & 527.18 \\ \cline{1-1}  & Water body & 55.69 & 2.00 & 0.47 & 3824.41 & 43.59 & 0.09 & 101.85 \\ \cline{1-1}  & Built-up land & 0.00 & 0.00 & 0.00 & 0.00 & 3930.47 & 0.00 & 0.00 \\ \cline{1-1}  & Unused land & 0.00 & 0.00 & 0.00 & 0.03 & 0.00 & 24.48 & 0.03 \\ \cline{1-1}  & Gains & 190.66 & 521.88 & 123.00 & 422.42 & 648.09 & 0.10 & 1906.16 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The land-use and land-cover change (LUCC) matrix in the Zhujiang–Xjiang Economic Belt (ZXEB) from 1990 to 2000 (unit: km\({}^{2}\)).