**Appendix A**


**Table A1.** General properties of the Chinese fir forest plantation before experimental treatment in 2011.

Data are cited from our previous study [3]; ns indicates not significant between the control and the nitrogen addition treatment at the *p* < 0.05 level. Values are the means ± SE (*n* = 4). DBH = diameter at breast height.

**Table A2.** Girth growth rates at breast height in the Chinese fir forest plantation in the nitrogen addition treatment and control from 2012 to 2015.


ns indicates not significant between the control and the nitrogen addition treatment at the *p* < 0.05 level. Values are the means ± SE (*n* = 4).

(**c**) 

**Figure A1.** The morphological characteristics of the three species of understory plants in our study. (**a**) *Dicranopteris dichotoma* [54] (**b**) *Lophatherum gracile* [55] (**c**) *Melastoma dodecandrum* [56].
