Table 1 Climatic conditions of the four survey sites
| Â | Mean Elevation (meters) | Mean Annual Precipitation (millimeters) | Annual Sunshine Duration (hours) |
|---|---|---|---|
Wuyuan | 1042 | 170 | 3263 |
Hohhot | 1040 | 400 | 1600 |
Tsining District | 1419 | 384 | 3130 |
Xilingol League | 1000 | 295 | 3000 |