Why Conserve the CDF

Why Conserve the CDF?

The Case for Conserving the Coastal Douglas-fir Biogeoclimatic Zone (CDF) and the Coastal Western Hemlock, Eastern Very Dry Maritime (CWHxm1) zones:


  • The Coastal Douglas-fir (CDF) ecological zone makes up about 0.3% of BC’s total area1
  • The CDF is by far the smallest and rarest of the 16 ecological zones in BC2
  • The CDF extends south into the USA but the vast majority of its global range is in BC2
  • The CDF contains the highest diversity of plant species in BC3
  • The CDF contains the highest diversity of over-wintering bird species in Canada 4
  • Although 94% of BC is public land, 80% of land in the CDF is privately owned4
  • Approximately 75% of the human population of BC lives in the CDF including in major centers such as Vancouver, Victoria, and Nanaimo4
  • 48% of the CDF and 32% of the CWHxm1 is occupied by human dominated (urban, agriculture, mining, etc..) land cover1
  • Approximately 40% of the CDF occurs in forests of various ages which historically have been used for forestry. Less than 1% of old-growth (>250 yrs) CDF forests remain5
  • Approximately 8% of the CDF is protected in variety of private and government conservation lands6 making it the least-protected ecological zone in BC
  • The CDF includes Garry oak ecosystems, of which less than 5% remains in a near natural condition3
  • The CDF contains more species at risk than any other ecological zone in BC2 (25 globally imperiled species and >225 species that are provincially imperiled or threatened)7
  • 98% (42 of 43) of the ecological communities in the CDF are considered “at risk”7
  • More than 151 introduced invasive species exist in the CDF8
  • The CDF has the highest road density of any ecological zone in BC1




1 Hectares BC query (http://www.hectaresbc.org/app/habc/HaBC.html ). Accessed May, 2013

2 Austin, M. A. et al. 2008. Taking Natures Pulse: The Status of Biodiversity in BC – Biodiversity BC

3 Ward, P., G. Radcliffe, J. Kirkby, J. Illingworth, and C. Cadrin. 1998. Sensitive Ecosystems Inventory: East Vancouver Island and Gulf Islands 1993-1997. Volume 1: Methodology, Ecological Descriptions and Results. Technical Report Series No. 320. Canadian Wildlife Service, Pacific and Yukon Region, BC
Floberg, J., M. Goering, G. Wilhere, C. MacDonald, C. Chappell, C. Rumsey, Z. Ferdana, A. Holt, P. Skidmore, T. Horsman, E. Alverson, C. Tanner, M. Bryer, P. Iachetti, A. Harcombe, B. McDonald, T. Cook, M. Summers, D. Rolph. 2004. Willamette Valley-Puget Trough-Georgia Basin Ecoregional Assessment, Volume One: Report. Prepared by The Nature Conservancy with support from the Nature Conservancy of Canada, Washington Department of Fish and Wildlife, Washington Department of Natural Resources (Natural Heritage and Nearshore Habitat programs), Oregon State Natural Heritage Information Center and the British Columbia Conservation Data Centre

5 Madrone Environmental Services. 2008. Terrestrial ecosystem mapping of the Coastal Douglas-fir Biogeoclimatic zone – Madrone Environmental Services

6 Cook, J. 2011. Coastal Douglas-fir Zone Protected Areas Ecosystem Representation Analysis

7 BC CDC Species and Ecosystem Explorer (accessed April 2013)

8 MacDougall, A.S., B.R. Beckwith, and C.Y. Maslovat. 2004. Defining conservation strategies with historical perspectives: a case study from a degraded oak grassland ecosystem. Conservation Biology. 18: 455-465