Compiled by the Community Development Forum

Coastal Douglas-fir Ecosystems


The Coastal Douglas-fir (CDF) Zone is the smallest and rarest ecological zone in British Columbia. Within Canada, it is found in Halfmoon Bay on the Sunshine Coast, a narrow band along southeast Vancouver Island, Qathet, the Gulf Islands, Texada and Lasqueti Islands, and a small fringe of the Lower Mainland. Its climate is mild and dry by Canadian standards, with warm summers and wet winters, creating conditions found in no other part of the country. These conditions support a mix of forests, meadows, and wetlands that contain the highest plant diversity in B.C., and are home for many species that live nowhere else in Canada.

The zone is also one of the most altered by human activity. Most of the land is privately owned, and overlaps with some of B.C.s fastest-growing urban and agricultural areas. Settlement, logging, farming, and development have removed almost all old-growth forest—none remains on the Sunshine Coast, and less than 1% remains in B.C. Going forward, the Province of B.C. aims to maintain at least 9% of these forests as old growth, and achieving this will involve protecting younger forests.

The Coastal Douglas-fir Zone is considered a conservation priority because it is small, biologically rich, and heavily impacted. Protecting it means safeguarding unique biodiversity, cultural heritage, and the natural systems that support clean water, carbon storage, and climate resilience.

Invasive Species

Coastal Douglas-fir forests are highly vulnerable to invasive species due to their small size, fragmentation, and proximity to urban areas. Invasive plants such as Scotch broom, English ivy, knotweed, giant hogweed, English holly, Himalayan blackberry, poison hemlock, and Canada thistle outcompete native vegetation, smother or kill trees, and disrupt ecosystem processes. Their spread reduces biodiversity, degrades habitat quality, and undermines the resilience of this already rare and at-risk ecosystem. Learn how to identify, remove, and report common invasive threats.

Are you a local property owner? 

The Coastal Douglas-fir Landowners Guide (CDFCP) highlights some things you can do to help:  

  • Retain large patches and maintain corridors: Avoid fragmenting natural forest areas with excessive clearing, wide driveways, or redundant trails. Connect natural zones with neighbouring properties to allow safe wildlife movement.
  • Plant Local Native Species: Focus landscaping on native species like Douglas-fir, western redcedar, salal, Dull Oregon-grape, and swordfern.  Native plants require minimal watering once established and support local pollinators and birds.
  • Eradicate Invasive Plants: Actively monitor for and remove Scotch broom, knotweed, English ivy, English holly and other invasive species.
  • Retain Woody Debris: Leave safe standing dead trees intact as nesting sites for birds and bats.  Leave fallen logs to decompose; they enrich the soil and retain critical moisture during dry summer months.
  • Minimize Soil Disturbance: Keep vehicles and heavy equipment off sensitive forest understories to protect root systems.  Soil compaction destroys beneficial fungal networks and creates conditions where invasive weeds thrive.
  • Natural Fire Breaks: Preserve mature, dense forest stands farther out on the property; their high moisture retention helps resist wildfire.


Commonly Asked Questions


Where is the Coastal Douglas-fir zone located?

In B.C., it is found in Halfmoon Bay on the Sunshine Coast, on Thormanby and Lasqueti Islands, on southeast Vancouver Island from Victoria to Comox, most Gulf Islands, and a narrow fringe of the Lower Mainland. It covers about 0.3 % of British Columbia’s land area. Learn about the CDF from the CDFCP.

Why is it called “Coastal Douglas-fir” if other trees grow there too?

Douglas-fir is the most common and ecologically dominant tree in this zone, but it coexists with arbutus, western redcedar, grand fir, bigleaf maple, and other species. Salal, Dull Oregon-grape and ocean spray are also dominant shrubs.

What makes the CDF zone unique and different from other B.C. ecosystems?

Confined to a narrow coastal strip, it has evolved in the mildest climate in Canada with dry summers and wet winters. It supports the highest plant diversity in B.C., and the greatest number of species at-risk in the province. The Douglas-fir ecosystems of the Salish Sea differ from those in other areas; with their unique geology, they evolved within protected waters and a dry, rainshadow basin. Its importance is recognized by the federal and provincial governments, and is included in Canada’s twelve Priority Places (Southwest British Columbia) .

How much of the original forest is left?

Provincially less than 1% of old-growth Coastal Douglas-fir forest remains. No old-growth (over 250 years) remains on the Sunshine Coast. Much of what is left is second-growth, with altered species composition and structure.

Which species or habitats are unique to it?

Habitats include Douglas-fir forests, wetlands, and rocky outcrops. There are 24 globally imperiled species, 282 provincially listed species at-risk, along with 45 ecological communities at-risk. Overview of CDF forests and associated habitats from RainCoast.

Why is it considered endangered?

It is the smallest bio-geoclimatic zone in B.C., heavily developed for housing, farming, and industry. Most of its 45 ecological communities are classified as endangered due to habitat loss, fragmentation, and invasive species. Due to its desirable coastal location, it overlaps with B.C.’s most densely populated areas, making it highly accessible and highly threatened.

Who owns most of the land in the CDF zone?

Provincially 80% is privately owned, unlike most B.C. forests which are public Crown land.

How does climate change affect the CDF zone?

Hotter, drier summers and more extreme weather increase drought stress, wildfire risk, and competition from invasive species.

What are the main threats besides logging and development?

Invasive plants, fire suppression, overgrazing by deer, climate change, recreational overuse, and hydrological changes from roads and construction.

How much of it is currently protected?

Provincially about 11 % of the zone is in parks, protected areas, or under formal conservation agreements.

Learn more

The above information is sourced from the following resources: