Background: There are multiple ecosystem and vegetation classification systems that describe ecosystems at different spatial scales. For example, in BC, the Biogeoclimatic Ecosystem Classification (BEC) system and the Ecoregion classification (EC) system are two systems. BEC is not in use outside of BC where the EC system and others are used nationally, in the US and internationally. Both systems divide the province into smaller and smaller units. For example from larger to smaller:                   – BEC units: Zone, Subzone, Variant, and Site Series                   – EC units: Ecoprovince, Ecoregion, Ecosection The BC Ministry of Environment Conservation Data Centre (CDC) uses the term ‘Ecological Community’ as the unit to describe ecosystems and they are treated similarly to species in that they are assessed and assigned conservation status ranks. The CDC uses the BEC system as well and in some instances site series are ‘rolled-up’ into a higher level of classification as they are recognized as the same ecosystem. The CDF: Technically speaking, the CDF zone in BC is actually the Coastal Douglas-fir Moist Maritime (CDFmm) Biogeoclimatic Subzone. There is no other BEC Subzone or smaller-scale BEC Variants and it is the only CDF BEC unit described in BC. Due to differences in the ecosystem/vegetation classification systems in the US, the extent of the CDFmm subzone is unknown but very likely occurs in the San Juan islands. This is reflected in the current published literature. It is possible that it also exists in other small pockets along/near the coast of the adjacent mainland WA state. If it were to be mapped in the US, the larger-scale CDF BEC Zone would likely go further south through WA and possibly into OR. Conclusion: To reflect it is the only BEC unit in BC and to simplify communication, the Coastal Douglas-fir Moist Maritime (CDFmm) Biogeoclimatic Subzone is commonly referred to as the ‘CDF zone’. The majority of the ecosystems in the CDFmm Subzone are unique to that BEC unit, are globally rare and at-risk. This is reflected by their provincial and global status rankings. BC has the majority of the global range of these ecosystems and therefore, the responsibility for their conservation and stewardship.