Table 1 Variables considered in the analysis of Fagus sylvatica treeline elevation in different mountain groups within the Apennines
Variable | Unit | Symbol |
|---|---|---|
Geographic & topographic | ||
 Peak elevation | m a.s.l. | PE |
 Latitude | degree | LAT |
 Distance from the sea | km | SD |
 Aspect | ° | A |
 Slope | % | SLP |
Climatic | ||
  Mean annual temperature | °C | MAT |
  Mean temperature of warmest month | °C | MTWM |
  Mean temperature of coldest month | °C | MTCM |
  Mean temperature of warmest quarter | °C | MTWQ |
  Mean temperature of coldest quarter | °C | MTCQ |
  Annual precipitation | mm·y−1 | AP |
Demographic | ||
 Population density within a 10.0 km radius around each mountain peak at three time points (1860, 1921, and 2011) | n·km− 2 | HP 1860 |
HP 1921 | ||
HP 2011 | ||