Table 1. Environmental characteristics of five natural secondary forest types.
| Natural secondary forest type | |||||
| Environmental factor | Chinese pine | Sharptooth oak | Chinese pine+Sharptooth oak | Armand pine | Wilson spruce |
| Longitude | 108°26′51″E | 108°26′24″E | 108°26′22″E | 108°28′46″E | 108°28′42″E |
| Latitude | 33°26′10″N | 33°26′10″N | 33°26′02″N | 33°27′17″N | 33°27′58″N |
| Altitude (m) | 1585 | 1554 | 1512 | 1963 | 2040 |
| Slope degree (°) | 35 | 38 | 36 | 15 | 5 |
| Slope aspect | SW | SW | SW | S | E |
| DBH (cm) | 16.12 | 12.77 | 14.28 | 18.57 | 19.14 |
| Tree height (m) | 15.85 | 9.61 | 12.35 | 13.56 | 12.23 |
DBH, diameter at breast height.