Elevation strongly influences soil moisture and patterns of tundra plant communities. Areas less than 100 m above sea level were separated to show low-elevation plains. Areas above 100 m elevation were divided into 333-m intervals to show decreases of about 2 °C, as predicted by the adiabatic lapse rate of 6 °C per 1000 m. This corresponds to the change in mean July temperature between Bioclimate Subzones.
Vegetation in mountainous regions changes with elevation, forming distinct elevational belts which correspond approximately to bioclimatic subzones. Vegetation is also modified by local topographic effects such as slope, aspect, and cold-air drainage. This heterogeneity was too detailed to map at this scale, so vegetation in mountainous areas was mapped as a complex, using a diagonal hachure pattern. The background color and the orientation of the hatching represent the pH of the dominant bedrock (magenta for non-carbonate bedrock including sandstone and granite, purple for carbonate bedrock including limestone and dolomite). The color of the hatching represents the bioclimate subzone at the lowest elevation within the polygon (yellow hatching for Subzone D and red hatching for Subzone E).