Table 1. Grouping and description of 15 predictor variables used in the model.
Spodosol, which was used as a categorical dummy variable and not included in the initial GLM analysis.
| Group | Predictor variable | Rank of influence by individual GLM | Standardized coefficient | Deviance explained (%) | Data source |
|---|---|---|---|---|---|
| Forested Area | Forested Area (FA) | 1 | 0.346 | 46.23 | MODIS |
| Groundwater | Water Table Depth (WTD) | 6 | 0.198 | 21.72 | Fan, Li & Miguez-Macho (2013) |
| Soil Property | Available Water Storage (AWS) | 7 | 0.136 | 8.35 | gSSURGO |
| Soil Hydrologic Group (SHG) | 8 | 0.120 | 7.37 | ||
| Spodosol | – | – | – | ||
| Climate | PET | 12 | −0.173 | 10.41 | MODIS |
| AET | 9 | −0.100 | 3.68 | ||
| Mean Annual Temperature (MAT) | 2 | −0.302 | 41.91 | WorldClim | |
| Mean Temperature of Coldest Quarter (MTCQ) | 4 | −0.331 | 44.60 | ||
| Mean Annual Precipitation (MAP) | 10 | 0.168 | 8.35 | ||
| Precipitation Seasonality (PSN) | 3 | −0.360 | 44.71 | ||
| Mean Precipitation of Driest Quarter (MPDQ) | 5 | 0.233 | 26.73 | ||
| Temperature Seasonality (TSN) | 11 | 0.146 | 7.98 | ||
| SPEI 1994–1999 (SPEI I) | 14 | 0.001 | 0.00 | WestWide Drought Tracker | |
| SPEI 1999–2004 (SPEI II) | 13 | 0.015 | 0.11 |