A list of the various 'regional' (zone/subzone/variant/phase) ecological units of the current biogeoclimatic ecosystem classification. At this 'regional' level, vegetation, soils and topography are used to infer the climate and to identify geographic areas that have relatively uniform climate. These geographic areas are termed biogeoclimatic units. The basic biogeoclimatic unit is the Subzone. These units are grouped into Zones and may be further subdivided into variants based on further refinements of climate (e.g., wetter, drier, snowier). The map units of the Biogeoclimatic map are mapped to the highest possible thematic resolution - subzone or variant. In some cases, where further sampling is required to define the unit climatically, polygons are labelled as an undifferentiated unit (e.g. CWH un)