Table 4. Changes of the mean Decline Index of coniferous tree species in major subalpine zone in the Baekdudaegan.
| Mountain | Species | Analyzed area | Investigated year | Remark |
| 2015 | 2016 | 2017 | 2018 | 2019 | 2020 |
| Seoraksan | AN | Total | – | 0.30 | – | 0.27 | – | 0.29 | p>0.05 |
| Gyebangsan | AN | Total | 0.04 | – | 0.07 | – | 0.07 | – | p>0.05 |
| PJ | Total | 0.09 | – | 0.09 | – | 0.00 | – | p=0.4 |
| Taebaeksan | AN | Total | – | 0.21 | – | 0.22 | – | 0.37 | p<0.05 |
| Deogyusan | AK | Total | – | 0.35 | – | 0.42 | – | 0.46 | p<0.05 |
| Jirisan | AK | Total | 0.45 | – | 0.42 | – | 0.46 | – | p>0.05 |
| Nogodan | 0.40 | – | 0.50 | – | 0.48 | – | p>0.05 |
| Banyabong Peak | 0.85 | – | 0.85 | – | 0.82 | – | p>0.05 |
| Seseok | 0.45 | – | 0.36 | – | 0.35 | – | p<0.05 |
| Chunwangbong Peak | 0.33 | – | 0.34 | – | 0.49 | – | p<0.05 |
| PJ | Total | 0.36 | – | 0.24 | – | 0.31 | – | p>0.05 |
| Banyabong Peak | 0.41 | – | 0.35 | – | 0.28 | – | p>0.05 |
| Seseok | 0.53 | – | 0.09 | – | 0.18 | – | p>0.05 |
| Chunwangbong Peak | 0.28 | – | 0.25 | – | 0.37 | – | p<0.05 |