Charcoal # 1 - Forestry Business?

I've been pondering for some time the most productive use we can put our 2.5 acres of woodland to.  My long term plan would be to alter the 'demographic' of the tree species in the woodland to create something really valuable - perhaps Oak for timber, Ash for firewood, Black Locust for Fenceposts, and Cherry and Walnut for timber and also food.  I'd been thinking that we could clear the undergrowth using our pigs, and gradually remove those species which I normally think of as 'weed' trees: Hazel, Elder, Birch for firewood (OK, maybe not the Elder!) during the replanting process.

Thinking further, another use for this 'waste' wood might be Charcoal, which may provide a decent income during our 'improvement' process.

I've seen a really interesting 'how to' guide from MIT (http://www.greenempowerment.org/blog/wp-content/uploads/2010/05/practical-action-technical-brief-final-charcoal1.pdf) aimed at producing charcoal from non-timber biomass, but hopefully applicable to timber too (maybe a good use for that Elder (in addition to a cracking wine!)?).

On the 'back of an envelope' my basic calculations are as follows:

Using a 55 gallon drum (200 litres), and assuming that maybe 30% of the inside space is lost to air gaps of one kind or another (the central 'chimney' space and gaps between pieces of wood)) that leaves us with 140 litres of wood.  Assume also that about 75% of the volume is left after burning, that leaves 105 litres of charcoal.  Our 'wet' (freshly cut) Birch was around 1000kg/cu-m density.  Charcoal is about 208kg/cu-m ( http://www.aqua-calc.com/page/density-table/substance/Charcoal) which gives us about 21.84kg of charcoal per 'burn'.

This kind of product (e.g. http://www.nigelsecostore.com/acatalog/Eco_Charcoal.html) can sell for £9.95 per 3kg , giving £72.44 of value per 'burn'.  Whether anyone buys at that price remains to be seen!  I've also seen stories of Tesco selling charcoal for £0.99 per 5kg! (http://www.canalworld.net/forums/index.php?showtopic=41347)  We'll have to see whether this enterprise makes any sense in due course.  In the worst case it should at least save us a bit of money in the barbeque season!

Incidentally the going rate for quality hardwood firewood seems to be £150/cu-m.  If you assume that 20% of that cu-m is fresh air (gaps between the logs), our wood would have been worth (140/0.8)x£150/1000 = £26.25.  If we can actually market the product and sell it in decent quantities that's a deceent value add!

I've got a steel drum, plenty of 18 month seasoned Hazel, and a ton of enthusiasm - I feel an experiment coming on!