## 3 Results
### Circumferential Root Cutting Test  
No root sprout of both two plant sizes was found under the no root-cutting treatment. There was no significant effect of root-cutting distance, root-cutting ratio and their interaction on the number of root sprouts of both two plant sizes, and the root sprout height and basal diameter of large plants in 2020 (\(p>0.05\)) (Table 3). The root-cutting distance and root-cutting ratio significantly affected the number of root sprouts of the small plant and the large plant in 2018, respectively (\(p<0.05\)) (Table 3). The number of root sprouts of the small plant at 0.25 m (10.3 \(\pm\) 2.04) was significantly higher than those at 0.5 m (2.4 \(\pm\) 0.67) and 1 m \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Variables** & **Effects** & _df_ & \(F\) & \(p\) & **Variables** & **Effects** & _df_ & \(F\) & \(p\) \\ \hline \multirow{3}{*}{NB} & PS & 1 & 5.497 & **0.026** & & PS & 1 & 11.831 & **0.002** \\  & SH & 3 & 1.487 & 0.238 & NRS & SH & 3 & 3.719 & **0.021** \\  & PS \(\times\) SH & 3 & 0.053 & 0.984 & & PS\(\times\)SH & 3 & 0.661 & 0.582 \\ \hline \multirow{3}{*}{BBD} & PS & 1 & 2.282 & 0.142 & & PS & 1 & 0.134 & 0.719 \\  & SH & 3 & 6.507 & **0.002** & & SH & 2 & 0.634 & 0.543 \\  & PS \(\times\) SH & 3 & 0.053 & 0.984 & & PS\(\times\)SH & 2 & 0.185 & 0.833 \\ \hline \multirow{3}{*}{BH} & PS & 1 & 2.838 & 0.104 & & PS & 1 & 1.548 & 0.253 \\  & SH & 3 & 1.431 & 0.256 & & & SH & 2 & 0.299 & 0.751 \\  & PS \(\times\) SH & 3 & 0.302 & 0.824 & & & PS\(\times\)SH & 2 & 0.187 & 0.833 \\ \hline \multirow{3}{*}{PDG} & PS & 1 & 4.438 & **0.043** & & PS & 1 & 0.887 & 0.378 \\  & SH & 3 & 11.663 & **0.000** & & & SH & 2 & 1.028 & 0.406 \\ \cline{1-1}  & PS \(\times\) SH & 3 & 1.759 & 0.175 & & & PS\(\times\)SH & 2 & 1.460 & 0.295 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Two-way ANOVA test for the effects of plant size (PS) and stubble height (SH) on plant growth (NB, BBD, BH and PDG) and root sprouting ability (NRS, RSH and RSD) of _Aralia elata_. Significant effects (\(p<0.05\)) are bolded. NB: number of new branches; BBD: new branch basal diameter; BH: new branch height; PDG: plant basal diameter growth; NRS: number of root sprouts in 2018; NRS2020: number of root sprouts in 2020; RSH2020: root sprout height in 2020; RSD2020: root sprout basal diameter in 2020. Figure 3: The plant growth and root sprouting ability of _Aralia elata_ under two plant sizes (**a–c,g,h**) or four stubble height levels (**d–f,i,j**). The data are presented as the mean \(\pm\) S.E. Different lowercases indicate significant differences (\(p<0.05\)) between two plant sizes or among four stubble height levels. (2.8 \(\pm\) 0.69) in 2018 (\(p\) = 0.001), and the number of root sprouts of the large plant with 100% root-cutting ratio (18.5 \(\pm\) 3.6) was significantly higher than those with 25% (6.8 \(\pm\) 1.33) and 50% (5.4 \(\pm\) 1.08) root-cutting ratios in 2018 (\(p\) < 0.001) (Figure 4a,b). There was a significant interaction effect of root-cutting distance and root-cutting ratio on the root sprout height and basal diameter of the small plants in 2020 (\(p\) < 0.05) (Table 3). For the small plant in 2020, the root sprout height and basal diameter at 0.25 m with 100% root-cutting ratio was significantly higher than those with 25% and 50% root-cutting ratios (\(p\) < 0.05) (Figure 4c,d). Figure 4: The root sprouting ability of _Aralia elata_ in different root-cutting treatments. The data are presented as the mean \(\pm\) S.E. Different lowercases indicate significant differences (\(p\) < 0.05) among four root-cutting distances (**a**) or three root-cutting ratios (**b–d**).