Le Mans (AFP)

They have already lived for two centuries, it will take them several years for their precious woods to be able to support the future spire of Notre-Dame de Paris: a long and complex treatment awaits the majestic oaks of the forest of Bercé (Sarthe).

Eight exceptional trees spotted in this forest - more than twenty meters of useful trunk and one meter in diameter - were selected Friday by Philippe Villeneuve and Rémi Fromont, chief architects of historical monuments.

Intended for the stool of the arrow destroyed in the fire of April 15, 2019, as well as the transept frames and adjacent spans, they will provide the foundation for a structure of some 300 tonnes.

Here, such an immense oak, marked with a number 8 painted in red, will be spared, because a knot has been discovered there.

There, another giant carries the "number one tree" sign and will soon be ashore.

"A drone made 3D profiles to check which ones were suitable," Aymeric Albert, head of the commercial department of the National Forestry Office (ONF), told AFP.

They must indeed be slightly curved, so that the future beams follow the curvature of the vaults, connecting the pillars of the crossing of the transept.

A thousand oaks from France were donated, mostly from five regions (Burgundy, Center Val de Loire, Grand Est, Pays de la Loire, Normandy).

Half of them come from public forests and half from nearly 150 private forests.

And new offers keep coming.

In a later phase, it will be necessary to redo the medieval structures of the nave and the choir.

Thousands of other trees, younger this time, will be selected.

Oak trees have already been proposed by foreign donors.

--"Harvest"--

The "harvest" of these thousand trees, as we call the felling in the forest language, was already scheduled for 2021. In order to allow the forests to regenerate naturally.

And the operation will be completed in the next few days, faster than expected, before the sap builds up.

For six months, the trunks will be left in place "because the tree can react, with tendrils, bends. When it has twisted, then we know that it will not move," explains Aymeric Albert.

Each tree is identified by a number allowing its traceability.

From April to June, the logs will be "skidded" (brought to the edge of the paths), then in the second half of the year, they will be cut and transported to about twenty sawmills.

Their drying time will be 12 to 18 months, until a humidity level of less than 30% is reached.

Towards the beginning of 2023, they will be transported to the workshops of the carpenters, who will follow the plans of Viollet-Le-Duc for an identical reconstruction.

Responding to the concerns of associations denouncing the felling of hundred-year-old trees, the Minister of Culture Roselyne Bachelot, who came to attend this symbolic moment, protested: "How to defend the timber industry without carrying out planned cuts in any case There is no buccaneer, no hacking, no loss of heritage. A forest is managed. "

According to the ONF, these thousand oaks represent 0.1% of the annual harvest of oak wood intended for construction or furnishing.

"It grows more oaks than we harvest: 3 million cubic meters, against 2 million, each year", estimates Aymeric Albert.

Their selection, congratulated the chief architect Villeneuve, "is the beginning of the real rebirth of the cathedral. We are entering a phase where we will see new things reborn".

Even if the restoration will not begin formally until September.

Asked about the risks of exceeding the five-year deadlines for the site, General Jean-Louis Georgelin, president of the Public Establishment in charge of Notre-Dame, sweeps them away: "we are on time to return the cathedral to worship in 2024. Even if there will be "still a lot of work".

And to continue: "In 2024, you will see in the sky of Paris shine the arrow which will no longer be the arrow of Viollet-Le-Duc but of Philippe Villeneuve!".

© 2021 AFP