The story of Coastal Douglas-fir forests: The intrinsic value of forests

Andy MacKinnon is one of the modern architects of the widely-used biogeoclimatic forest classification system in British Columbia. Retired professional forester and biologist, teacher, long-time resident of southern Vancouver Island, and co-author of Plants of Coastal British Columbia and Mushrooms of British Columbia, Andy has an intimate understanding of BC’s coastal forests, how they have changed over time, and what is needed to safeguard them into the future. 

What can you tell us about the CDF biogeoclimatic zone?

British Columbia has more types of ecosystems than any other province or territory. The wettest, driest, warmest and some of the coldest climates in Canada are all in our province. Our ecosystems occur from sea level to alpine elevations, and from southern near-desert ecosystems to northern boreal forest. To make sense of all of this ecological complexity, an ecological classification system was developed in BC. This system is called the biogeoclimatic ecosystem classification (BEC), because it uses the geographic distribution of plant communities (bio) and soils information (geo) to infer and map climatic subzones and zones. The broadest units are BEC zones. 

BC has 16 BEC zones, and one of the smallest is the Coastal Douglas-fir (CDF) biogeoclimatic zone, covering approximately 350,000 hectares at low elevations (generally sea level to 150m) along southeast Vancouver Island from Bowser to Victoria, the Gulf Islands south of Cortes Island, and a narrow strip along the Sunshine Coast near Halfmoon Bay. This represents the geographical distribution of a particular plant community on zonal (average moisture and nutrients) sites. The CDF lies in the rainshadow of the Vancouver Island and Olympic mountains. Summers are warm and dry, and winters are mild and wet. 

How have the ecosystems in this region changed over time? What is the state of the old growth within the CDF zone?

The CDF has one of Canada’s mildest, most hospitable climates. For ten millennia and more the abundant resources of this area supported the vibrant cultures of BC’s Salish Nations. It was one of the earliest coastal areas settled by Europeans – famously characterized by James Douglas in 1842 as “a perfect ‘Eden’ in the midst of the dreary wilderness of the North west coast”. The “perfect Eden” was, in fact, an intensively managed landscape, managed by First Nations for food production and other goals. Suppression of First Nation management activities such as aboriginal burning began a long process of changing CDF ecosystem structure and composition. 

This geographic area was also home to some of BC’s earliest logging and milling activities. Logging was often followed by the development of previously forested areas for agriculture and habitation. As a consequence, the CDF zone has very little (certainly <1% of the land area) original (old-growth) forest remaining. And of course our climate is changing, with (in the CDF) temperatures generally increasing, summers becoming drier, and winters wetter. One consequence of increased summer temperatures and droughts is stress and mortality in some tree species, especially western redcedar, arbutus, and Douglas-fir.  

How does the fragmentation of forests impact stability and resilience?

In the face of development, climate change, introduced species, and other challenges, maintaining any sort of stability is an unrealistic (and likely counter-productive) goal. Maintaining resilience – the ability of species and ecosystems to adapt to environmental change – is important. The best strategy for maintaining and enhancing resilience is likely to maintain the species, ecosystems and landscapes of the CDF in a state as close as possible to ‘natural’. We can’t predict with any certainty how species will react to some of these changes – our ecosystems are simply too complex and too poorly understood. Our best bet is to maintain as many native species as possible, and to maintain some ecosystems in as undisturbed a state as is possible. As the Conservation Data Centre’s Jason Straka explained in another of your interviews, the CDF zone has more at-risk species and ecosystems per hectare than just about any other ecosystem in Canada. We’ll have to do a better job of managing these at-risk species and ecosystems. And we’ll have to protect some CDF forests from development, and allow them to grow old.    

What makes coastal forests special?

I think that everyone would answer that question differently. These forests have ecological, social and economic values associated with them, different combinations for different folks. And I believe that they have intrinsic value also – that is, that they’re valuable in their own right, whether we associate some value with them, or not. For me, if by “coastal forests” you mean the CDF, it’s the species and ecosystems that are associated with this ecological zone, some of which are found nowhere else in Canada.   

What can individuals do to nurture forest health within this zone?

The landscapes of the CDF have been massively modified for more than a century now, by logging, and the development of agriculture and settled areas. We should take action on protecting our greenspaces whenever possible, acquiring land for new protected areas. And we should be actively involved in restoration of these areas, including removal of invasive species. Also, there’s much that we need to learn about the structure and composition of CDF ecosystems, whether through formal research projects, or citizen science. And finally, I believe that we need much more monitoring taking place, so that we can begin to understand how CDF ecosystems are changing in response to a changing climate. For example, over much of the CDF, we’ve observed increased mortality of western redcedar trees. Is there increasing mortality of trees on your Island and, if so, what species? This sort of information will be critical to determining how we should be responding to climate change and other stressors.

About Andy MacKinnon

Andy MacKinnon (MSc, DSc) worked for 30 years as an ecologist with the Research Branch of the BC Ministry of Forests, Lands and Natural Resources. (MSc, DSc). His graduate research was in mycology and he is the co-author of six guidebooks to BC plants. He is a retired professional forester and professional biologist. He has served as an elected Councillor in Metchosin since 2014. Other roles he occupies are the Chair of Metchosin Finance and Environment Standing Committee; Council Liaison to Metchosin Environmental Advisory Select Committee; and board member for the Greater Victoria Public Library. He also contributes to work done by the CRD Climate Action Inter-Municipal Task Force Committee, Capital Region Invasive Species Partnership (CRISP), Metchosin Hall Society, and Beecher Bay Sci’new First Nation.

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