To address climate change, an original experiment has been conducted since 2020 by the French National Forestry Office, in the municipality of La Chapelle-Heulin, in the west of the country. On an 8-hectare plot called "seed orchard," 1,640 young maritime pines have been planted and are taking their time to grow. The goal of the project is to collect seeds from these southern pines to replant them wherever drought has decimated local species.
This department is among the least wooded in France. Loire-Atlantique, a land of market gardening and vineyards, has hosted one of the "seed orchards" created by the ONF since 2020. 1,640 young maritime pines have been planted on an 8-hectare plot, in the midst of the Nantes vineyard, in the municipality of La Chapelle-Heulin. Why this isolated plot? Because there are no other pines nearby that could bring diseases to the seedlings.
"Indeed, this orchard has a purely reproductive purpose," explains Jean-Christophe Helleisen, research, development, and innovation assistant at the ONF. “All our seedlings come from remarkable trees. These trees are pines from several forests in the south of France that we have selected for their interesting characteristics: their vigor, their ability to reproduce, their resistance to drought… They can provide a genetic response to climate change. Thus, if all goes well, in about six to ten years, the now adult seedlings will produce high-quality seeds in large quantities. And these can be replanted elsewhere.”
Drought-resistant species
According to the IPCC (Intergovernmental Panel on Climate Change), in 50 years, the Pays de la Loire region is expected to experience the current climate of southern France. The beeches growing in the area are already beginning to suffer. The idea of the ONF with its seed orchards is therefore to anticipate. To have the capacity to reforest French forests if this does not happen naturally. "Our orchard is a bet on the future," details Jean-Christophe Helleisen. "A safety net, in case regeneration becomes increasingly difficult." This project is supported by a consortium consisting of the ONF and two neighboring nurseries.
The maritime pines will eventually measure between 20 and 25 meters. They were chosen both for their resistance and because they are conifers, whose seeds are quicker to obtain. "They will produce seeds in six years at the earliest. Once harvested, they will go to a drying facility and then be marketed. There is already a very strong demand from private and public nurseries, the seeds are already partially reserved. We are sure we will sell them."
Looking ahead to 50 years
In the meantime, Jean-Christophe Helleisen and his colleagues are keeping an eye on their young shoots. They monitor the trees that die, maintain the land, conduct soil analyses… "We regularly check to ensure everything is going well. The seedlings are doing well, they are strong. We have only lost about 2 or 3% during the drought of summer 2022."
Soon, their work will no longer be limited to the few hectares already planted. Other projects are indeed already planned in the department. Further north, a "future island" will soon emerge, featuring Canary oaks, which are very resistant to drought. "We will see if they can adapt here," notes Jean-Christophe Helleisen. Still in La Chapelle-Heulin, a seed orchard of pubescent oaks (also known as truffle oaks) is in the launch phase. Known for their good resistance to fires and drought, this tree is indicated for fire prevention. "But here," emphasizes Jean-Christophe Helleisen, the first seed harvests are expected in 40 to 50 years! We are working on a very, very long-term project. We are working for our grandchildren."
Featured photo: replanting everywhere where drought has decimated local species ©Hans de Pixabay