## 3 Results
### Contributions of Climate and Human Activities to NPP  
To quantitatively evaluate the contributions of climatic factors to NPP changes, the method based on partial derivatives was applied to calculate the contributions of temperature, precipitation, and solar radiation to NPP variations. From 2000 to 2019, T\({}_{\rm out}\), P\({}_{\rm com}\), and R\({}_{\rm com}\) in YRB were 0.002 g C m\({}^{-2}\) year\({}^{-1}\), 0.93 g C m\({}^{-2}\) year\({}^{-1}\), and 0.16 g C m\({}^{-2}\) year\({}^{-1}\), respectively (Figure 6). Precipitation achieved the greatest positive contribution among all of the climate factors, followed by solar radiation and temperature. Furthermore, the results of T\({}_{\rm com}\), P\({}_{\rm com}\), R\({}_{\rm com}\) were applied to require the contributions of C\({}_{\rm com}\) (Figure 6a-c,f). Both climate and human activities positively contributed to forest NPP changes in YRB, and the contribution of human activities was 2.41 g C m\({}^{-2}\) year\({}^{-1}\), while the contribution of climate was 1.09 g C m\({}^{-2}\) year\({}^{-1}\). In addition, for each type of forest, F\({}_{\rm old}\) and F\({}_{\rm new}\), the contributions of climate and human  
Figure 4: Annual averaged net primary productivity (NPP) of (**a**) the old forest; (**b**) the new forest; (**c**) all forest. Figure 3: Changes in annual net primary productivity (NPP) of (**a**) all forest, (**b**) the new forest, and (**c**) the old forest. activities to NPP share the same pattern as that of the forests as a whole. The contributions of climate to F\({}_{\text{old}}\) and F\({}_{\text{new}}\) NPP were 0.8553 g C m\({}^{-2}\) year\({}^{-1}\), 1.2526 g C m\({}^{-2}\) year\({}^{-1}\), respectively. And the contributions of human activities to F\({}_{\text{old}}\) and F\({}_{\text{new}}\) NPP were 2.4210 g C m\({}^{-2}\) year\({}^{-1}\), 2.4932 g C m\({}^{-2}\) year\({}^{-1}\), respectively. As shown in Figure 6a, temperature positively contributed mainly in the upper of YRB, while it had a negative contribution in the middle and lower reaches. Precipitation had positive contributions in the west of 110 east longitude, whereas its negative contributions were mainly distributed in the east of 110 east longitude. Additionally, the positive contributions of solar radiation to NPP were distributed in most of YRB (57.20%). All in all, contributions of climatic factors to NPP were found to be positive in the upper of the YRB, but negative in the Jiangxi Province. Besides, for F\({}_{\text{old}}\), _UF_, representing the contributions of other climate factors, accounted for 38.11% (negative impacts: 10.12%; positive impacts: 27.99%). For F\({}_{\text{new}}\), _UF_ represents the contributions of human activities. In 48.48% of YRB, human activities were beneficial to forest growth (Figure 6e). However, negative contributions of human activities to NPP were scattered in the southern areas of YRB. Contributions Proportions of Climate Change and Human Activities to Forest Restoration or Degradation  
According to scenario analysis, the contribution proportions of climate and humans to forest restoration and degradation are evaluated. Based on this, the regions of climate-dominated and human-dominated forest restoration and degradation were attained (Figure 7). For F\({}_{\text{old}}\) the climate-dominated forest and other climate factors-dominated forest accounted for 9.77% and 28.33%, respectively (Figure 7). For F\({}_{\text{new}}\), the climate-dominated forest and the human-dominated forests are 17.56% and 44.34%, respectively (Figure 7). Obviously, for F\({}_{\text{new}}\), the impacts of humans on forest restoration or degradation were larger  
Figure 5: Net primary productivity (NPP) trend of **(a)** the old forest, **(c)** the new forest, and **(e)** all forest, **(b,d,f)** their corresponding. than those of climate in YRB (37.22% vs. 14.35%; 6.62% vs. 3.21%) (Figure 8). However, for Fold, the other climate factors dominated the forest restoration and degradation.