by Etienne Belanger, Director of Forestry, FPAC
Recent discourses about global forest loss have suggested Canada is a big offender, even “the largest contributor to deforestation worldwide”. But reports and articles, although drawing from solid scientific sources, can mischaracterise the information from which they draw their claims. I’d like to go through some of the different terms that are often mis-used or used interchangeably when talking about forests. This blog will also discuss concepts that are important to understand the particular case of Canada’s forests. As we’ll see, Canada has a very positive and progressive record in ensuring our forests are sustainably managed and there for future generations. Foresters help make sure of that.
In Canada, foresters practicing in the public forest are confronted with forest landscapes so vast, they will never be able to walk through them all. Maybe because they’re so big, Canada’s forests appear to be unchanging, inexhaustible or even eternal—yet they’re anything but. Even in the absence of man-made disturbances, wildfires and insect outbreaks constantly disturb parts of the forest. After a stand burns (or in forester-lingo is subject to 'disturbance'), species tend to come back in a certain order. Trees that grow quickly in the open, such as aspen, tend to be first to establish themselves after the opening of the tree cover. More shade-tolerant species, such as balsam fir, grow underneath them, and as the initial trees species starts to die out a second wave gradually takes over— a process aptly named 'succession'. As the plants change so do the animals, with warblers and moose giving way to woodpeckers and marten. In sum, forests aren’t static and “timeless”. They constantly transform, evolve and adapt— but on a timeframe that is hard to grasp, sense or visualise.
Aspen sprouting two years after the fire (Wikimedia Commons)
Aspen may be replaced by more shade-tolerant conifers,
which may also make the area burn more easily.
A forest manager has to consider all of this, survey, assess, and understand the whole forest through space and time, in such a way as to deliver long-term management strategies with implications for generations to come. The forester will need to decide when, where and how to harvest mature forests without adversely affecting the natural balance of these constant changes. How much can be harvested? Which harvesting practices won’t undermine the forest ecosystem resilience? Which practices could help foster efficient and diverse succession patterns and biodiversity?
Bearing all this in mind, I'd like to offer a few observations on the concepts that are often used when talking about the state of forests. The first one is 'deforestation'. People often don’t realize that deforestation is less about the act of removing the trees from a forested area and more about what happens afterward on that same parcel of land. If the forest is regenerated either naturally or through plantings, such tree removal is not deforestation. Natural fires and man-made forest harvesting both cause a temporary treeless state in what was, and will again be, a forested area. On the other hand, if the land subsequently gets used for something other than forestry such as agriculture, urban expansion, or road building, the forest won’t come back. This latter case is what deforestation refers to. Indeed, if anyone has a vested interest in avoiding it, it’s the forester, given that their livelihood, and their compliance with forest management regulations, demands that harvested areas be returned to forest once the trees have been removed.
Related, but different from deforestation, are the concepts of ‘forest loss’ and ‘forest gain’. Assessment of forest loss and gain are increasingly popular due to the tremendous improvement in remote sensing technologies (i.e. signals propagated by aircraft or satellites to acquire information) that have taken place in recent decades. Until recently, many of the forest statistics available to estimate the world’s forest cover have been no more than informed guesses. While in developed countries there have long been on-the-ground measurements that inform estimates of forest inventory, these methods are not used everywhere – and particularly not in developing countries. Even today, although remote sensing technologies makes possible the estimation of the world’s forest cover, we have to recognise that it has its limitations. Still, many online platforms are now providing vital information about where and when forests are “lost” or “gained” which can inform policies and land-use planning, as well as law enforcement. One important drawback of these forest loss/gain assessments is that, when not coupled with other information about the reasons as to why, or under what conditions the forests are “lost” or “gained”, they can lead to misinformed conclusions. A forest might appear lost after land conversion to other uses (i.e. deforestation), forest conversion to exotic species or monoculture plantation, harvesting (legal or illegal), insect and diseases epidemics and/or fire (natural or man-caused). Therefore, the same 1% forest loss might have a tremendously different implication depending on the underlying causes – and indeed, whether that loss is permanent or temporary. And the same goes for the forest “gains”. Gains might be take place in a monoculture plantation, in a degraded forest, or simply through natural regeneration. Finally, even in a sustainably managed forest, forests losses and gains won’t necessarily be balanced and present a net sum of “0” every year.
Figure 3: Area defoliated by the mountain pine beetle in Canada (million of hectares) https://nfdp.ccfm.org/insects/national_e.php
There will be lag of a number of years or decades between the “loss” and the “gain” on a given tract of land that is strictly due to the time it will take for the forest regeneration to reach the height necessary to be detected by remote sensing. Therefore, if there is a period where natural disturbances are significantly higher than normal (as is the case in western Canada since the mid-2000s due to the ravages caused by the mountain pine beetle) this approach will appear as significant forest “loss” for years, before appearing as a huge forest “gain” that will take place once the forest has recovered.
'Fragmentation', or dividing a continuous block of forest into disconnected units, is a trickier term. It requires a reference point to make sense. If a forest covers 5,000 square kilometres, does dividing it in two matter? What portion of that forest will be impacted by that fragmentation? Which species? Then, what if it is a forest of 50 square kilometres that gets fragmented into two units? Talking meaningfully about fragmentation requires thinking long and hard about the physical characteristics of the specific forests in question. You have to look very carefully and impartially at the evidence, and develop an idea of what the flora and fauna associated with that forest require. And then you have to add a safety margin to your estimates based on how accurate you think the evidence is. When developing forest management plans, different scales of fragmentation are likely to be considered to manage the needs of different species. These types of considerations lead to incorporating lower footprint forest practices such as winter harvesting (which doesn’t require long-lasting roads), road reclamation, agglomeration of cut blocks to minimise road density, etc.
The last term I'd like to comment on is 'intactness', which typically focuses on the presence/absence of human activities within a forested area. There is no doubt that forest areas with high degrees of intactness are highly valuable, from a scientific perspective. They serve as a scientific benchmark to study how ecosystems are evolving under natural conditions. In addition, they are of emotional and spiritual importance to many people simply because they are “un-touched” and “wild”. We are very lucky in Canada to be one of the countries that retain the largest amount of “intact”, “unmanaged” forests.
Even with a vibrant forest sector, Canada will continue to have a vast area of “intact”, “unmanaged” forests. Approximately 40% of our forests are too far north to be realistically accessible. Although significant, non-commercial forest is not the only area where “intactness” is valued. Within the more southern “managed forest”, a web of conservation lands is created by the combination of defined protected areas and a variety of conservation measures. Varying by region, these conservation lands make up between 20 to 40% of that southern area. So the question is not just how much is intact and where. Foresters need to see the forest ecosystems as a whole and need to ask themselves how all parts — whether protected or managed— are doing. Is the ecosystem staying healthy, and productive? Does it remain resilient and capable of sustaining its associated biodiversity?
So how can we determine whether cutting down a forest is good or bad? How much is too much? Where should we cut and where shouldn’t we? It’s a complex question that depends not only on the forest you plan to harvest, but also on the conditions of nearby forests and what you expect will take place in that harvested area and its surroundings over time. That’s why a forester looks at the long term and uses the perspective of large spaces to ensure that the diversity of plants, animals and the ecosystem constituted by the forest as a whole can continue.
Canadians should know that since 1990, an average of only 0.4% of our managed forests were harvested each year (0.25% if we consider all forests). Which means it would take 250 years to harvest the full extent of the fraction of Canadian forests that are under management – which is only 60% of Canada’s total forest area. Moreover, every forest stand harvested is regenerated. In essence, every tree cut is regrown – and on commercially harvested areas, this regrowth is mandated by law. As such, we can all feel confident that our vast forest resource will be there for future generations as these forests continue to transform, evolve and adapt through time and space.