Old growth forest – cherished, abundant and growing fast

At Resource Works, we're always looking to uncover the facts about complex and challenging science issues. What we have discovered about the vigorously debated issue of old growth forests in British Columbia might come as a surprise. Stewart Muir provides an update.

With daily reports in the news media about colourful protests against logging of "British Columbia's last old growth forest", it's worth understanding the issue at hand.

B.C. is a very large province with great forest diversity. To simplify things let's look just at Vancouver Island, which happens to be the location of the protected Fairy Creek watershed. As part of our ongoing independent forestry project at Resource Works, our mapping experts accessed government databases to extract information about the state of the forests.

What they found might come as a surprise if you are among those who believe claims being made by protest organizations.


As the map above shows, despite a century and a half of industrial logging, old growth forests remain superabundant in most parts of the Island.

The least amount of old growth is on the east and southeast areas of the Island, which also happens to be where the vast majority of its human residents live. Urbanization and agriculture have dramatically changed the face of the landscape in those regions. Here's the same map but emphasizing municipalities and agricultural land:


One has to wonder whether there is a correlation between what people see around them every day and their beliefs about what the landscape must look like everywhere else. If there is a large, old tree in the forest but you can't see it because it's far away in a place with no roads, does it even exist?

In any event, all old growth forest on Vancouver Island is subject to harvest restrictions and is, in that sense, protected. Only once the more than 100 bureaucratic steps required to secure harvest permissions are followed successfully, might a tree aged 250 years or more (that's the definition of old growth on the coast) become subject to harvesting.

But just because logging is approved for an area, it doesn't mean that noteworthy specimens are doomed. Modern cutblocks contain carveouts for a variety of reasons including special stands and habitat. Three quarters of coastal forest is already protected in perpetuity. As of last September even greater protections were put into place for large specimens.  

Another factor often overlooked is that trees are not static like rocks - they are plants that grow. Resource Works calculates that every single day, the equivalent of 17 soccer fields of "new" old growth arise on Vancouver Island alone as trees age into the old growth category.  


Every year, that's like covering 6,205 soccer fields with trees aged 250+ years. According to answers.com, Europe has 6,000 soccer fields. So one could truthfully say that in 2021, Vancouver Island added more old growth forest acreage than there are soccer fields in Europe.

Quite a contrast to the familiar talking point that "we're making a last stand at Fairy Creek because after this there will be no more old growth left", isn't it?

When it comes to mapping old growth forest, experience has taught us that some people will look at the map above and say things like: "Not all old growth is equal, some of that forest might be old but is of little biodiversity value. Only 3% of the most valuable old growth is left and that's what we're talking about." I have examined this claim in detail and find it highly questionable.

It's true that there is diversity across the category of old growth. However, to dismiss whole sub-categories of old growth is beyond picky; it's actually quite misleading.

Some old growth trees don't look very old simply because they're not very big. Height alone is not a very effective measure for biodiversity. Flying over Vancouver's Stanley Park recently I noticed that most of the tallest trees there had lost their tops, probably due in many cases to the devastating storm of December 2006. Are they less valuable because of the loss in height? I don't think so.

There are old growth forests located in boggy areas, leading some to say we shouldn't count it. Which is ridiculous, when you consider the fact that these bogs are rich in ancient cedars that may be relatively modest in height yet can have enormous diameters.

This is further evidence that the concept of old-growth is to some extent in the eye of the beholder. With literally hundreds of mapping categories to choose from in extracting mapping data from the forest database, anti-forestry activists have shown themselves to be quite creative in the production of alarming maps sure to provoke an emotional response. A more evenhanded approach to the same data, as in the maps above, reveals the truth of the matter.

Here's just one example. On British Columbia's coast including Vancouver Island, there are more than 75,000 hectares of trees taller than a 13-storey building (that’s 46m or 151 feet). The protest movement insists that only a small fraction of this has biodiversity value. I (along with pretty much all of the credentialed foresters I encounter in my work) disagree with that view.

In Fairy Creek, some pressure groups are seeking to make an old-growth cause celebre out of the marbled murrelet, a seabird that nests in the forest. Credible forest modelling tells us that this creature's ideal nesting habitat is trees 93 feet (28.5 metres) tall or higher. Yet the minimum height for high-value old growth is claimed to be 131 feet (40 metres), according to the studies that protest groups brought forward and love to cite. Why is this consequential? Because it means that the relatively limited amount of super-tall old growth is not the only place where these birds like to nest. Marbled murrelet, you have plenty of good places to build your nests.


Here's another way to visualize the reality that on the B.C. coast, mature forests are not in danger of disappearing:


It's not just that forests age. They also grow. Every year, the volumetric growth of British Columbia forests is about equal to the amount of the timber harvest. The current situation is a bit like living off the interest of your savings. 

The long-term trend shown here fits hand in hand with planning by the forest industry itself to transition to greater dependence on second-growth forests. Unlike the polarized and often emotional public conversation with its black-and-white characterizations of problem and solution, what's happening to keep forestry science on a sustainable path is complex and sophisticated. It is way beyond the simplistic thinking and mutually exclusive solutions which if implemented would needlessly threaten the livelihoods of numerous communities. 

Restoring balance to this debate is a necessity for decision makers. They are being bombarded today by a tiny slice of the population that is angrily demanding policy changes that are not based on science and that reject collaboration. Recently, I made a presentation to the elected council of the Municipality of North Cowichan. Judging by the reception, it was pretty clear that they were not used to hearing from impartial, informed voices committed to solving complex forestry problems for win-win outcomes. (You can view the presentation at this video link, starting at the 11 minute mark.) Forestry people need to work harder to get the full fact set out there. Recently, a group of experienced experts stepped forward to be part of ensuring authenticated science-based information is not overlooked.

We humans need a healthy successful forest industry for all kinds of reasons. Climate change is a big one. Thanks to forestry, the new seedlings planted to replace harvested trees are carefully selected for the climate conditions expected decades and centuries in the future. The quest for a decarbonized energy system needs versatile, renewable wood for building materials, fuel, bioplastics. If we want to choose a better future, we cannot afford to exclude responsibly managed forest harvesting like we have in British Columbia.

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