The CBVM legend and its application for mapping the boreal vegetation of Canada

1 Université Laval, Québec, QC, Canada
2 NRCAN, GLFC, Sault Sainte-Marie, ON, Canada
3 Meidinger Ecological Consultants Ltd.,Victoria, BC, Canada
4 British Columbia Ministry of Natural Resource Operations, Smithers, BC, Canada
5 Ministry of Natural Resources, Sault Sainte-Marie, ON, Canada

The need for a common legend to map the whole boreal was clearly stated since the beginning of the Circumboreal mapping project (CBVM). Discussion took place in different meetings. At the Helsinki meeting of 2010, a draft legend structure was agreed and regional team had to test it with pilot mapping projects. At the Akureyri meeting in 2011, regional teams shared their views about classification and mapping of boreal vegetation, comparing the results of the different pilots. From those exchanges, a reviewed legend structure was designed. The proposed legend for CBVM has six hierarchical levels (from the broadest to the most detailed):

1) Formation Type, based on broad physiognomy and structure (forest, woodlands, …);

2) Formation Group, based on structure and physiognomy and reflecting main climatic conditions (zonal vegetation) or site, edaphic, or topographic conditions (extrazonal, azonal);

3) Formation Dominant Growth Forms (evergreen, deciduous, …);

4) Bioclimatic Subdivision, based on climatic parameters and bioclimatic indices as reflected by vegetation, usually North–South broad zonation;

5) Geographic Variants, based on species or ecosystem distribution, usually West–East broad zonation; and

6) Plant Community based on species composition.

Level 5 is the most detailed level that is to be mapped at the scale of 1 : 7 million that was chosen for the circumboreal map. Level 6 is related to site characteristic and intended to be mapped at a more detailed scale. Following the Akureyri meeting, the Canadian team extended and revised their pilot projects in order to fill the legend structure and test its relevance in our vegetation condition. The Canadian National Vegetation Classification, a project involving the federal and provincial jurisdictions of Canada, provided the knowledge about the vegetation associations that was required to discriminate the Bioclimatic Subdivision and the Geographical Variants for Canada. From the Canadian pilots arose the need for a landscape unit framework to express the dominant potential vegetation at the level 6 of the CBVM.

© 2012 Organizing Committee