French forests are gradually losing their ability to capture and store CO2. In recent days, several national media have echoed the publication of the latest inventory of greenhouse gas (GHG) emissions from the National Institute for Geographic and Forest Information (IGN), according to which the CO2 storage capacity by our forest ecosystems would have been halved in about ten years.
Some specialists even believe that by 2026 – tomorrow, therefore – French forests could emit more carbon than they absorb. While the government is soon to present the third version of its national low carbon strategy (SNBC), the situation is alarming.
If the observation is not debatable, the identification of the factors accelerating this worrying trend suffers from certain ideological biases. Some indeed tend to point to logging as one of the causes of the collapse of the carbon sink. Their reasoning is simple, not to say simplistic: since we are cutting down trees, these same trees can no longer capture GHGs.
Unstoppable, unless one takes a little height; and does not the urgency of the current situation require avoiding these deceptive shortcuts? The carbon sink is not declining due to increased tree harvesting but due to global warming, which leads to increased tree mortality and dieback.
The Academy of Sciences writes it in black and white in a recently published report: “Net growth of metropolitan forests decreased by 10%, mortality increased by 54% and removals increased by 20% between 2005-2013 and 2012-2020. »
How to explain such excess mortality? Also according to the Academy of Sciences, “drought is the first major determinant of the health of forests […] The lack of water causes early cessations of tree growth […] and photosynthesis, which generate a significant decrease in productivity, annual growth […] and carbon sink”.
Where in these lines is there a call to abandon our forests to their fate? How would their vulnerability justify that man, who has managed these massifs for centuries, turns away from them in the name of an alleged capacity of “nature” to adapt to upheavals whose speed takes everyone by surprise? the living beings ?
To adapt, to survive, and to continue to store carbon, our forests need to be managed and cared for by the foresters for whom this is their primary mission. These do not cut trees “for fun” but because these cuts respond to the challenges of climate change. Whether it’s “sanitary cuts” intended to combat the dieback of diseased trees, or “improvement cuts” clearing thinnings that allow the most beautiful and vigorous trees to develop, it’s all forest life that foresters are committed to preserving for future generations.
The firefighters dispatched to the scene were almost unable to cope with the chaotic tangle of vegetation which represented a real natural fuel. Unmanaged by man, the Teste-de-Buch forest has released, and this time definitively, all the carbon it has stored for centuries in the atmosphere. Is it really this “laisser faire” model that is needed to protect our forests from the risks that threaten them?
Finally, as counter-intuitive as it may seem to some, cutting down trees is necessary if we want to achieve carbon neutrality by 2050, as France has committed to. The forest and the timber industry thus have a major role to play in the SNBC. The second version of this strategy advocates an increase in wood harvesting to store carbon in objects, rather than in forests that are likely to be burned.
CO2 concentrations will not drop overnight by spraying master paintings on display in museums. Ideology will not save us. We have to adapt and, I believe, humans can do that. Let’s trust the scientists, field experts and foresters, whose job is the forest.
* Pierre Bois d’Enghien, Belgian agricultural engineer, teaches environmental sciences.
