"The cold forests are burning! Siberia is burning, Canada is burning!"

On June 9, the Université de Montpellier signed a memorandum of understanding with theUniversité du Québec en Abitibi-Témiscamingue (UQAT) and theUniversité Franche-Comté to create the international "cold forests" research project. The aim is to model the functioning of these ecosystems in order to better preserve them. A highly topical subject. Explanations with Adam Ali, paleoecologist atIsem and project leader in France.

This project is called "cold forests". What do these terms really mean?
Our project focuses on high-latitude forests, i.e. the Arctic and sub-Arctic realms, as well as forests at high altitudes, i.e. mountain forests. Whether at high altitudes or high latitudes, these forests contain species with common life-history traits. For example, their ability to resist frost or to grow in very short periods of time, in order to be able to live in these ecosystems.

What are the current issues facing these forests?
Our problem is quite simple: these forests are major carbon reservoirs. In particular, the boreal forest, which surrounds the Arctic Circle, is one of the world's largest carbon sinks - carbon trapped mainly in centuries-old peat bogs. In recent years, however, the situation has changed, and our carbon sink has become a carbon source. This shift is linked to forest fires, which are becoming more frequent, larger (several thousand hectares) and more violent. This is one of the main thrusts of our research activity.

Do cold forests burn?
Yes, it's counter-intuitive, but cold forests burn... a lot! In fact, they're among the world's top-burning ecosystems. Siberia burns, Canada burns! In 2014, for example, in Canada's Northwest Territories, 385 forest fires destroyed 3.4 million hectares. It's important to note that over the last 40 years, these northern regions have recorded an average annual temperature of +3°C. We can see what's happening right now in British Columbia, with an unprecedented heat dome and a fire season that started very early and ended with some villages being evacuated (Radio Canada 01/07/2021).

And yet there's very little talk about them, whereas the fires in Australia received a great deal of media coverage...
That's true. We don't talk about it much because these fires are not on the same scale as what happened in Australia, but also because there aren't many people living in these areas. Except, of course, the indigenous people who live in these forests, who depend on them for their livelihoods and for cultural purposes. There are issues linked to the First Nations on these territories. They're going to be affected by climate change before anyone else.

But how do you explain the spontaneous start-up of these forest fires?
It's not easy, because the system is quite complex. Is it linked to ocean warming? Is it linked to atmospheric anomalies? These are what we call teleconnection processes, and they're really not easy to grasp, but we're thinking about it. We're trying to model and understand these mechanisms, or at least the parameters that have led to the mega-fires we've seen in recent years.

There's also the question of how these forests are used?
These are anthropized ecosystems, used by man. The idea is to guide decision-making on all activities related to the use of biological resources in these ecosystems. To move towards an ecosystem-based management approach that ensures that human disturbances ultimately remain within what we call "the range of natural variability", a range of disturbances that the ecosystem can absorb, and so foresters and managers are also partners in this approach.

It's an interdisciplinary project, and you yourself are a paleo-ecologist. What does your discipline contribute?

We have ecologists, climatologists, forest managers, climate modellers, etc. I'm in charge of the paleo-ecological axis. The aim is to document how these ecosystems have functioned since the Holocene, i.e. over the last 11,700 years. During this geological period, there have been major climatic changes: warming and cooling. We want to see how these ecosystems have responded to these variations in climate.

How do you observe this?
We have open-air libraries! The lakes and their sediments contain charcoal and pollen grains. These two bio-indicators enable us to reconstruct the history of forest fires and vegetation over time. There's also dendrochronology...

...the dendro what?
Dendro is Greek for "tree", chronology, time. In wood, each ring is equal to one year, an archive that records everything. In simpler terms, if the weather is warmer, for example, the tree will produce a much larger ring, while if it's colder, it will be smaller. It's an ideal tool for reconstructing past temperature changes. These trees are also tools for dating fires which, when they don't burn down the whole tree, leave scars. These scars contain important information that enables us to date fires to the nearest year.

How long will the "Cold Forests" project last, and where will it take place?
It's planned for five years, renewable once. The epicenter will be in Quebec, where we'll be hosted by the university, but we'll also be working in Canada's boreal zone, in the Northwest Territories, Labrador and Newfoundland. In mountainous areas, we're targeting the Pyrenees, the Alps, the Vosges and the Atlas and Rif mountains of Morocco. The extended project also includes a project in the Altai, on the border between Russia and China....

You mentioned an extended project. What is it?
The memorandum of understanding we signed on June 9 is an international research project (IRP) involving theUniversité du Québec en Abitibi-Témiscamingue (UQAT ), the CNRS, theUniversité de Franche-Comté and the UM. Alongside this IRP, we have set up a broader international research network (IRN) that includes Sweden, Norway, Russia, China... All these partners enable us to take a truly international approach to our problems, and develop joint projects.

What does this protocol that the University of Montpellier has just signed enable you to do?
This is the first time that the University has equipped itself with a tool that frees up the time and brainpower of teacher-researchers to develop their research. Thanks to Muse and the system, I was able to take two-thirds of my teaching leave for the duration of the IRP. This is a major element of the agreement on the French side. The Université de Franche-Comté provides support in terms of mobility assistance and project funding. On the Canadian side, there are also a great many resources, notably the Quebec research fund, which contributes the equivalent of $100,000 each year. We also benefit from the creation of a research chair in historical ecology. In short, thanks to this protocol, we have five to ten years ahead of us to develop large-scale work on these fascinating ecosystems.