Paris, Apr 17 (IANS): France no longer has trees big enough to replace the ancient wooden beams that burned in the massive Notre Dame fire, according to a French cultural heritage expert.

Bertrand de Feydeau, Vice President of preservation group Fondation du Patrimoine, told France Info radio that the wooden roof that was ravaged in the blaze was made with oak beams more than 800 years ago from primal forests.

The oak beams were added to the cathedral in 1220. Because of the building's gothic style which called for high vaulted ceilings, tall, sturdy oaks were sourced from nearby forests.

De Feydeau said the cathedral's roof cannot be rebuilt exactly as it was before the fire. "It is a framework that is not rebuildable," he said, adding "we no longer have trees of our size on our territory that were cut in the 13th century and were what we call the primary forest".

The expert was cited as saying by France Info radio that the restoration work will have to use new technologies to rebuild the roof "that will leave the appearance of the cathedral as we love it".

Monsignor Patrick Chauvet, rector of the cathedral, told CNN that the church's medieval roof structure, mostly made of oak, "has been lost".

Meanwhile, David Elstone, Executive Director of British Columbia-based Truck Loggers Association, said his province would not have suitable oak, but if architects required soft wood timber, Canada could help.

"We probably have a tree that would suit the needs of the architects that are trying to rebuild Notre Dame. "We grow large strong trees that you cannot find in other areas," he said.

According to a study published last year, only four per cent of Europe's remaining woodland is primary forest, with none larger than 500 square kilometers outside of Russia or Northern Europe.

A combined 800 million euros have already been pledged by a number of companies and business tycoons to help rebuild the Unesco World Heritage site.