Successive droughts are putting French forests to the test.
By creating “islands of the future”, the National Forestry Office (ONF) seeks to know the species that will tomorrow be able to withstand hotter and drier climates.
The objective is to maintain a mosaic forest that is more resilient to the vagaries of time.
In Eure-et-Loir, in Senonches, 55,750 plants will be installed this winter to reforest 35 hectares of the estate.
The work began in December 2023 and continues in January 2024.
“We are going to test, in real forest management conditions, new species and origins of trees,” explains Bruno Huchet, head of the ONF team in Eure-et-Loir.
“Research should have carried out this work upstream, but faced with the climate emergency, there is not enough time.
We no longer have enough perspective to compare methods or cross-reference data.
This approach is the most relevant.
»
Also read Climate: underground life, urban forests… Harvard students imagine the Paris of tomorrow
Fifteen species – sessile oak (Gascogne and Berry), southern oak (pubescent, green and cork), sweetgum and Virginia tulip tree, cherry, pear, walnut, cormier, linden, black locust, Atlas cedar, maritime pine, redwood sempervirens –, were selected.
The long-term interest will be to select the most adapted and thus increase the panel of forest species likely to resist climate change.
In the Senonches national forest, these new species will replace spruces planted in the 1970s and which are dying off, as well as Douglas firs, which are reaching maturity.
Beech is also suffering from the reductions in precipitation observed in Eure-et-Loir.
“Ten years ago, we received 1000 millimeters of water per year, now it’s 800. The beech which was acclimatized to this humidity is showing signs of weakness,” observes the forester.
Diversification closely observed
Eleven plots will be partially reforested, i.e. approximately 35 hectares.
They will be planted at densities ranging from 1500 to 2000 plants per hectare.
The Senonches oak forest will remain so despite the addition of these new trees.
“Sessile oak will remain largely dominant in Senonches for a long time to come, for the next forty to fifty years through natural regeneration confirmed in the new management document (2022-2041),” says Bruno Huchet.
The new species will diversify the wood and will be closely monitored by foresters over the next thirty years, in order to confirm or adjust the ONF's strategies.
Throughout France, similar actions are carried out in public and private forests to multiply the results of the experiments.
Ultimately, these islands will also make it possible to harvest seeds from these future species adapted to French climatic conditions.