With the fire that severely damaged Notre Dame in Paris comes a dilemma. The wooden roof structure and spire were destroyed, a 12th century oak frame that was made of trees that themselves could have been 300-400 years old. Now the question is how do you replace these historic wooden structures? Clearly not with old-growth 400 year old French oak, because that just does not exist. Old growth forests are now few and far in between, and even less so for species like oak. We have spent a millennia pillaging the forests of the world for their largest trees, with little thought to their replenishment – true we do replant trees, but often with more economical, fast-growing species like pine. Hundreds of years ago few thought about replanting the towering trees of the world.
So the dilemma – replace the wooden roof structure with oak, or maybe modern laminated wood (LVL), or something like steel? I have read that people have already offered oak, like 100-year old oaks from the oak forests of Normandy to help rebuild, and I get that the rebuild should mimic the traditional building techniques as much as possible in order for Notre Dame to maintain its historic nature. The question of course is should we harvest 100 year old trees? Should their longevity trump the needs of a historic building? The actual wooden roof structure is only visible to those who walk through the attic space, no one else. The main roll of this roof structure is to maintain the 210 ton lead roof. How far do you take renovation using original methods and materials? I saw an example of this in Bergen, Norway, where they are restoring the houses of Bryggen, the Hanseatic League’s trading empire from the 14th to the mid-16th century. The techniques are old-school, but then again those hoses only date from after the fire of 1702.
The stone of Notre Dame would have been cut by 12th century stone masons – by hand. The trees similarly would have been hewn, by hand. Would we go so far as to replicate these techniques? It works on a small scale building, that’s for certain, but something requiring the rebuild of an original roof supposedly constructed of 13,000 original trees, one per beam – unlikely. Just as unlikely as we would not cut stone using a machine (an exception is the recreation of a 13th century castle in France, Guédelon Castle where original techniques are being used). What about integrating some modern technology – using glue laminated, or mechanical key laminated oak beams? They could still be oak, but made from smaller trees, from sustainable forests. Or maybe awesome Glulam beams made from more sustainable timbers. The tight grain of a 400 year old tree cannot be replicated, and certainly not by a 100 year old tree.
The reality is that rebuilds like Notre Dame will never be 100% historically authentic – they are too large to be done that way. The ancient beams are burnt and lost, and they can’t simply be replicated in any easy manner. Modern techniques will have to be used, failing some attempt to travel back in time to procure both materials and 12th century artisans. The spire wasn’t even medieval, and dated from 1859, replacing an earlier spire. Oh but please keep those modern glass and aluminum infused architects away from it at all costs – find someone who is able restore its historic qualities, using modern materials in a manner that respects the buildings history.
Oh, and maybe, just maybe, we should plant more trees like oak for future generations.