Species distributions and environmental layers.

<p>Figure (a–d) are distribution maps of species pooled to genera <i>Pinus</i>, <i>Abies</i>, <i>Larix</i> and <i>Picea</i>, respectively, superimposed over background digital elevation model (DEM) maps with 50% transparence. Figure (e) and (f) are maps of the environmental factors gross degree days (GDD) and aridity respectively.