## 4 Discussion
### Implications for the New Round of the GGP
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mean**} & **Null Hypothesis** & **Alternative** & \multirow{2}{*}{\(\mu_{\text{A}}\)} & \multirow{2}{*}{\(\mu_{\text{B}}\)} & \multirow{2}{*}{**P**} \\  & **(\(H_{\text{0}}\))** & **Hypothesis (\(H_{\text{1}}\))** & & & \\ \hline \(\text{FVC}_{\text{max}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}<\mu_{\text{B}}\) & 75.1732 & 77.1498 & \textless{}0.0001 ** \\ \hline \(\text{LAI}_{\text{max}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}<\mu_{\text{B}}\) & 2.3096 & 2.4766 & \textless{}0.0001 ** \\ \hline \(\text{NPP}_{\text{avg}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}<\mu_{\text{B}}\) & 410.8583 & 450.5745 & \textless{}0.0001 ** \\ \hline \(\text{WR}_{\text{pua}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}<\mu_{\text{B}}\) & 8.9232 & 11.4906 & \textless{}0.0001 ** \\ \hline \(\text{SWAL}_{\text{pua}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}>\mu_{\text{B}}\) & 20.9982 & 19.5538 & \textless{}0.0001 ** \\ \hline \(\text{SWIL}_{\text{pua}}\) & \(\mu_{\text{A}}=\mu_{\text{B}}\) & \(\mu_{\text{A}}>\mu_{\text{B}}\) & 1.4887 & 1.4148 & 0.1046 \\ \hline \end{tabular} Note: the \({}^{\star}\) symbol on the top-right of the P value means the tendency is significant (P \(<\) 0.05), and the \({}^{\star\star}\) symbol means the tendency is very significant (P \(<\) 0.01).  
\end{table} 
Table 8: Null hypothesis and alternative hypothesis of mean annual values of ecosystem quality and ecosystem services indicators between Sample A and Sample B from 2000–2010. \(\mu_{\text{A}}\) and \(\mu_{\text{B}}\) are, respectively, the mean of annual values of indicators of Sample A and Sample B, and the units from top to bottom are %, dimensionless, gC m\({}^{-2}\), 10\({}^{4}\) t km\({}^{-2}\), t ha, and t ha. change among subregions, regional restoration measures need to be concerned carefully. More attention should be paid to re-establishing near-natural forests or the restoration of a region's natural climax vegetation [22; 96; 104; 105; 106]. Owing to the urgent need to address eco-environmental problems, the Chinese government had to act before the achievement of scientific consensus, which needs a step-by-step investigation and does not provide instant solutions [107]. Therefore, the massive afforestation program which ignored differences in topography, climate, and hydrology in the first round of the GGP is understandable. In future GGP policy-making and implementation, we suggest that the former practice of aggressive afforestation on a large-scale must be changed. Rational and specific plans and designs for afforestation areas should seek scientific advice before implementation according to regional climate and geographical characteristics, including local temperatures, precipitation, terrain, soil, and hydrology. In addition to the appropriateness of tree species, near-natural vegetation communities which take into account diversity and mixtures of the tree-shrub-herb system should be planted instead of single-species plantations. All the authors significantly contributed to this study. [PERSON], [PERSON], and [PERSON] proposed the idea and designed the research; [PERSON] wrote the manuscript; [PERSON], [PERSON], and [PERSON] conducted generation of LULC and modelling and trend analysis on FVC, LAI, and NPP; [PERSON], [PERSON], and [PERSON] conducted the modelling and trend analysis on WR, SWAL, and SWIL; [PERSON] conducted the experiment on exploring the impact of climate change and GGP implementation on ecological changes. This research was jointly funded by the National Key Research and Development Program of China (Grant No. 2017 YFC0506501), the National Natural Science Foundation of China (Grant No. 41571504), and the National Ecosystem Survey and Assessment of China (2000-2010) (Grant No. STSN-7). We thank [PERSON] and [PERSON] for their technology support in the LULC datasets generation. We thank [PERSON] for his data support of NPP.