Re: Alternative fuels
@ John Arthur
Clear felling all the usable trees and not planting replacements until its too late (which is what happened) is not by any mechanism "sustainable".
Real "sustainable" would have meant cropping the trees at a rate at which continuous ongoing exploitation without loss of the reserves would have been possible. That didn't happen. To be honest it doesn't happen very often: even so-called sustainable FSC accredited schemes are often than not more a paper masque over a totally unsustainable felling regime.
In reality the only provable sustainable large-scale forestry operations are those which use softwoods for paper production, with the felling on a relatively short 40-50 year cycle, or the even shorter-term coppiceing of willow or aspen for biofuel.
But going back to the ships timbers: you'd be hard pushed to get a ships frame out of an oak thats less than 300 years old. Having said that, ideally you'd use elm as a better material but theres not much chance of that nowadays