Report “This is what we do with humans when we vaccinate them”: in Bouches-du-Rhône, the National Forestry Office trains plants to adapt to the heatwave

The high temperatures are tiring the French forest. Near Manosque, in the Bouches-du-Rhône, the ONF is conducting experiments to try to make trees and plants more resistant.

France is emerging from a new heat wave on Thursday, August 15. No department is on heatwave alert anymore. The last few days have been very hot in places, and you may have suffered from it. Trees are also victims of the high temperatures. The French forest is weakened by global warming. So the nursery of the National Forestry Office (ONF) in Cadarache, near Manosque, in the Bouches-du-Rhône, is working to make this forest more resilient.

Under one of the greenhouses, thousands of young trees are lined up in small pots, each one scrutinized very closely by Catherine Santaella, a researcher at the CNRS. “There is Aleppo pine, oak, Sirius domestica”lists the scientist. These three species were chosen because “that they react to drought in a different way, and therefore each one is interesting for having plants that are resistant”explains Catherine Santaella.

Right now, she is training the shoots to respond better to lack of water. “We’re going to treat the plants with plant hormones to make them think they’re experiencing a drought, even though there’s water. We hope that by learning to react faster, they’ll keep their water inside, instead of letting it evaporate.”

Catherine Santaella compares this technique with that of vaccination. “That’s what we do with humans when we vaccinate them. We trick the body into thinking it’s infected with a virus. It reacts and it remembers that response. And that’s kind of what we’re trying to do here.”

“The aim of this experiment was to research this natural resistance.”

Jérôme Reilhan, head of the nursery

to franceinfo

Among the nursery’s other projects in recent years: Atlas cedars, subjected to more or less intense drought. The experiment of several months has made it possible to identify the most resistant specimens, explains Jérôme Reilhan, manager of the site. “Every tree is different. Some people have the ability to do sports, others to study. And the trees here have that same difference. Some are naturally adapted to drought.

This then makes it possible to create a bank of particularly robust trees to be replanted in the French forest. And this is urgent, because it has been overtaken by climate change.

The plant itself can adapt, assures Jérôme Reilhan, “but climate change is happening much faster than it can adapt to.” SO, “Man must help him, and do what is called assisted migration. That is to say, take species that are already in the south and bring them to the north more quickly, to anticipate this climate change.”

Hoping to halt the weakening of our forests. According to the ONF, 300,000 hectares are dying due to droughts and heat waves, or about 30 times the surface area of ​​Paris.