A French cultural heritage expert says France no longer has trees big enough to replace ancient wooden beams that burned in the Notre Dame fire.

Bertrand de Feydeau, vice president of preservation group Fondation du Patrimoine, told France Info radio that the wooden roof that went up in flames was built with beams more than 800 years ago from primal forests.

Speaking Tuesday, he said the cathedral's roof cannot be rebuilt exactly as it was before the fire because "we don't, at the moment, have trees on our territory of the size that were cut in the 13th century."

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He said the restoration work will have to use new technologies to rebuild the roof.

APTOPIX France Notre Dame Fire
Flames and smoke rise from Notre Dame cathedral as it burns in Paris, Monday, April 15, 2019. Massive plumes of yellow brown smoke is filling the air above Notre Dame Cathedral and ash is falling on tourists and others around the island that marks the center of Paris. (AP Photo/Thibault Camus)
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