Sandra Plantier, an associate professor of secondary education in geography at the National Higher Institute of Teaching and Education, says that tree harvesting is archaic, and that replacing the former structure with oak trees as opposed to a modern, sustainable alternative could even end in the same result.
“Making the deliberate choice to cut down a thousand hundred-year-old trees to reconstruct the spire of the cathedral and its framework can only appear as a blindness to reality, or, worse, as an inability to draw lessons from the current situation,” she says in a column for Reporterre.
“These thousand trees, one or several hundred years old, are as many cathedrals for the biodiversity of our forests that we are getting ready, for the first, to cut down at the very beginning of spring, even though they will nest there probably already birds and squirrels.”
Work to restore the cathedral is not expected to begin until the beginning of 2022. Carpentry experts say rebuilding Notre Dame as it was will take 2,000 metres squared of wood, requiring about 1,500 oaks to be cut down. The cathedral’s roof contained so many wooden beams it was called la forêt (the forest). The roof’s support included 25 triangular structures 10 metres high and 14 metres across at the base, placed over the stone vaults of the nave.
Notre Dame is seen at the submerged bank of Seine River after continuous rainfalls in Paris
Geologists are studying about ten quarries north of Paris to find the same limestone as that mined for the cathedral underneath the French capital. That vast network of quarry tunnels beneath Paris was closed in the 18th century as collapsing galleries created dangerous sinkholes in streets and fields around the city.
Workers need new stone to rebuild collapsed parts of the vault and replace blocks in the gables over the three main entrances and other sections high up the side walls that were weakened by the fire.
Experts have been carefully testing the strength of surviving stones with everything from radar beams to simple mason’s hammers. Some stones that fell from the vault can be reused, but others have lost their inner solidity.
At the end of January 2021, fifty-two wooden support vaults left the Le Bras workshop for Paris, for the purpose of reinforcing each of the five stone vaults of the cathedral that were weakened or damaged, or sometimes gutted by the collapse of the spire during the fire of April 15th, 2019.
Assembly at the cathedral will begin in February 2021, thirty meters above the void: the supports will have been previously mounted under the vaults using hydraulic jacks.