## 3 Results Analysis
### Land-Use Rising/Falling Tupu Analysis
#### 3.3.2 Land-Use Falling Tupu  
The fall potential mapping of the two time-series units in Ningde City from 2000 to 2010 and from 2010 to 2020 is shown in Figure 6, while the differences and changes in each county and city were also counted (Table 7). As shown in Table 7 combined with Figure 6, during the period of 2000-2010, the decreased area of cultivated land in the study area was the highest, 210.42 km\({}^{2}\), accounting for 66.1% of the shrinkage area; followed by the decreased area of forest land, 96.98 km\({}^{2}\); and again, by the decreased area of grassland, 5.68 km\({}^{2}\); and the decreased area of built-up land and the decreased area of unutilized land were both unchanged. There are obvious differences in land-use changes among counties and cities, with the highest shrinkage of cultivated land in Gutian County, 33.91 km\({}^{2}\); the highest shrinkage of forested land in Fuding City, 17.85 km\({}^{2}\); and the highest shrinkage of grassland in Xiapu County, 1.23 km\({}^{2}\), which is three times as much as that of Fu'an City, the city with the lowest shrinkage of grassland. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Period**} & **District or** & **Decreased** & **Decreased** & **Decreased** & **Decreased** & **Decreased** & **Decreased** & **Decreased** & **Decreased** \\  & **County** & **CL** & **FL** & **OL** & **GL** & **WB** & **BL** & **UL** \\ \hline \multirow{8}{*}{2000–2010} & Jiaocheng & 22.47 & 6.58 & 0.24 & 0.55 & 0.54 & 0.00 & 0.00 \\  & Fu’an & 31.44 & 12.52 & 0.39 & 0.41 & 0.59 & 0.00 & 0.00 \\  & Fuding & 33.06 & 17.85 & 0.53 & 0.51 & 0.24 & 0.00 & 0.00 \\  & Gutian & 33.91 & 14.42 & 0.29 & 0.77 & 0.03 & 0.00 & 0.00 \\  & Xiapu & 30.03 & 14.74 & 0.35 & 1.23 & 0.51 & 0.00 & 0.00 \\  & Zhouning & 12.67 & 6.92 & 0.18 & 0.50 & 0.04 & 0.00 & 0.00 \\  & Shouning & 20.73 & 11.84 & 0.70 & 0.67 & 0.09 & 0.00 & 0.00 \\  & Pingnan & 18.85 & 8.05 & 0.41 & 0.57 & 0.06 & 0.00 & 0.00 \\  & Zherong & 7.25 & 4.06 & 0.07 & 0.47 & 0.02 & 0.00 & 0.00 \\ \hline \multirow{8}{*}{2010–2020} & Jiaocheng & 16.26 & 8.20 & 0.11 & 2.97 & 0.01 & 0.00 & 0.05 \\  & Fu’an & 20.53 & 16.44 & 0.06 & 3.51 & 0.00 & 0.00 & 0.07 \\  & Fuding & 33.35 & 14.99 & 0.55 & 4.36 & 0.25 & 0.00 & 0.02 \\  & Gutian & 25.02 & 18.43 & 0.08 & 8.99 & 0.00 & 0.00 & 0.06 \\  & Xiapu & 24.01 & 11.97 & 0.12 & 4.32 & 0.21 & 0.00 & 0.12 \\  & Zhouning & 6.82 & 7.49 & 0.08 & 2.90 & 0.00 & 0.00 & 0.01 \\  & Shouning & 10.90 & 13.05 & 0.23 & 4.32 & 0.00 & 0.00 & 0.02 \\  & Pingnan & 15.33 & 2.73 & 0.00 & 2.62 & 0.00 & 0.00 & 0.26 \\  & Zherong & 3.59 & 4.46 & 0.06 & 2.25 & 0.00 & 0.00 & 0.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Land-use falling Tupu in Ningde City from 2000 to 2020. Figure 6: Land-use falling Tupu in Ningde City from 2000 to 2020. During the period from 2010 to 2020, the area of each land-use type in the study area decreased compared with the previous period (2000-2010), but the spatial distribution range expanded. Among them, the decreased area of cultivated land was still the highest, at 155.81 km\({}^{2}\), indicating that the trend of cultivated land occupation has further intensified in this stage; followed by forest land and grassland, with decreased areas of 97.76 km\({}^{2}\) and 36.24 km\({}^{2}\), respectively, and the spatial distribution spreading further; the water and unutilized land decreased areas are the smallest, and the change is not obvious. Among the counties and cities, Fuding City had the highest decreased area of arable land, 33.35 km\({}^{2}\), which is the administrative unit with the largest land-use change rate at this stage; the decreased area of cultivated land in Gutian County was second only to that of Fuding City, 25.02 km\({}^{2}\), and the decreased area of cultivated land in the rest of counties was also reduced compared with that in the previous stage; the decreased areas of forest land and grassland in Gutian County were both the highest.