rogerwhit has raised an issue on http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=520&page=1#Item_28 . He says that 'renewable' products like timber should survive in use for at least as long as it takes to regrow the tree that was cut. Otherwise if renewal is needed sooner than that, you're cutting another tree before the first one is 'paid for' (my words).

As a criterion for assessing sustainability, that's a very tall order, which I think humans can rarely hope to fulfil. Cedar shingles must last more than the 50yrs it takes to re-grow the tree (I doubt such fast-growth cedar would be suitable for shingles). Furniture must last 50yrs. Paper must last 50yrs! In days of old they made timbers last for hundreds of years, re-using them, from ship to building to building. Or did they? The old timbers that we see are hardwood, oak, which would have to last what - 250yrs? to exceed regrowth time. For every surviving old timber, dozens must have rotted quickly - thin boards, for a start. Every archaeological posthole is a rotted timber.

I think, I hope, there's a flaw in the argument. What does the team think?

An interesting, but false arguement. It's like saying don't eat a cabbage that takes six months to grow but only six minutes to eat. Or an oyster that grew for five years but is swallowed in five seconds.

By the way, oak trees are harvestable at 80 years. Beyond 150 years you tend to get so much degradation in the centre the timber loses value. Can't see much point in making furniture that only lasts 50 years.

Well put. It explains why I've sown a long row of cabbages. I think oysters are over-rated.

Posted By: rogerwhitWe can't, ultimately, use more timber than the planet can grow. Be sensible. Some of the above points are spurious, even though Biff's humour is irrepressibly enjoyable.

Use can't forever out-strip replenishment of the resource.

Absolutely not. But It would be possible for use to outstrip replenishment even though the durability was longer than the regrowth time. Say a roof lasts 100 years and uses 10 trees, and the trees only take 50 years to regrow. The durability is longer than the regrowth time, so by the proposed definition, it's sustainable. But if you've only got ten trees growing and three houses to maintain, then you're in trouble, because you can only re-roof one house every 50 years, so one of the houses will have to wait 150 years for its roof.
It's not only the ration of durability to regrowth that counts; the ratio of materials in use to materials growing has to be factored in too.

Every tree that's ever grown has re-oxidised sooner or later (unless anareobically turned to coal). The vast majority have rotted (oxidised), beginning immediately as soon they fell. A small proportion have burnt (oxidised) even sooner, in forest fires. A tiny proportion have been sequestered by man's intervention, stored dry for longer than 'natural' for burning later. A microscopic proportion have been sequestered by man for even longer, as anything from structural timber to paper, still burning or rotting eventually. A completely negligible proportion have actually survived unoxidised for longer than it takes to regrow the original tree. So the sustainability of the ecosystem seems to be entirely unaffected by the time to re-oxidation relative to the time to regrow. Having said that, I still can't put my finger on a neat rebuttal of rogerwhit's apparently logical proposition.

Posted By: jonfostertom's description of Roger's argumen

Did I describe it wrong?

So that phrase you used meant nothing significant?

OK!

So if shingles last only 25yrs (not saying that's true) and the trees take 50yrs to re-grow, then provided there are 50/20 = twice as many trees growing, then all is well. That is, however many trees were cut to put the world's current stock of shingles on roofs, twice as many suitable trees should be growing. Thanks for 'putting your finger on it' funcrusher - means it's not after all in principle necessary that timber products should outlive their regrowth time - though quite likely that in practice sufficient replanting is not happening. What do you say, rogerwhit?

Posted By: funcrusherIf you want to know God's mind, study science and mathematics

True as far as it goes, but hugely insufficient. A scientist-type person would say that. Just more of the same western left-brain delusion. Add to science and maths: meditation, creativity, intuition, Intentionality. Are these merely trivial or secondary aspects of 'God's mind'? I'd say they were primary - or at least they are the route that's available to humans, to enter God's mind. Science and maths are what may then be discovered there - but scientists, if wise, should recognise that meditation, intuition, creativity and Intentionality are how great scientific and mathematical discoveries are made. Too many scientists know stories about how superstars like Einstein worked that way, but for themselves, straight hard-edged thinkiness is right, proper, sufficient, and to be scornfully enforced on 'unscientific' new-agers.

Funcrusher, in your earlier post you seem suggest that the primary cause of global deforestation is that peasants (by which I take you to mean subsistence farmers) chop down trees because they are morons, whereas rich English landowners in Ireland didn't chop trees down, presumably because they were not morons. Would that be a fair interpretation of your position?

Joe: I am descended from Irish peasants, and merely report facts. It is you who suggest that the facts describe morons. Doubtless each person provides his own judgment on a set of facts.
I think its a pretty well accepted observation that the richer you are, the lower the marginal utility of money, hence the lower your discount rate of future cash flow, and hence the greater weight you place on long term returns. To put it more simplistically: a penniless peasant with a starving family is interested in growing food and having firewood today; not waiting 150 years for an oak to grow, and another 500 years for its timber to be discarded for firewood following use in a building. It is also the case that the poor, especially in more advanced societies, are frequently poor because they make very bad decisions about getting value for their money or indeed life in general. Sociologists will continue to debate whether this is because they are genetically stupid, lack education, or simply have different preferences.

To a great extent the green argument is that most people are 'morons' destroying the planet for short term gratification.

My wife once tried to reform a hopeless alcoholic , who used to beg for a few odd jobs around the garden in order to earner a fiver he immediately took to the pub. She would feed him tea, soup and sandwiches at midday, whilst delivering her homily against drink etc. One day he responded thus " The thing is, to you -it's a waste. But to me it's not" This neatly encapsulates the fundamentals of the free market. It also explains why peasants chop down trees.

Frequently great socio-economic disasters are ascribed by historians, nearly all of whom are innumerate, to some mass conspiracy by whatever groups are present: landlords, capitalists, communists, jews, etc. The reality is that the actions of human beings are largely rooted in changing economic conditions. In the case of Ireland, the problem was the economic union of 1801 which led quickly to an over-valued currency as England rapidly industrialised and Ireland could not because it lacked coal. This was exacerbated by an ever-growing tide of cheap food from the colonies and the US courtesy of steamships etc., which destroyed English farmers and Irish peasants alike. In fact, Irish land prices collapsed by around 80% between 1820 and 1855, and over 20% of all estates (by area, over 3000 in number) where bancrupted and sold off and their owners ruined. Inevitably, per Shakespeare, people always 'heap their troubles upon the King' so inevitably popular political myth blames the landlords.

Joe: I guess the 'moron' contest is a draw: You didnt say IRISH peasants were morons, and neither did I. 'Moronic' I applied to current peasant deforesters; your juxtaposition with 'English' landlords suggested you had in mind Irish peasants 150 years ago. Your comment about the Iron age is right, and by extension must have been valid until modern times, at least in more primitive parts of ther globe. However, with perhaps the exception of some remote tribes, all current peasant deforesters are morons, with connivance/encouragement of governments. In East Africa for example (where my daughter has spent some time), well-meaning aid agencies have caused much increased deforestation by directly and indirectly encouraging much enlarged herds of grazing animals - which are of course (as in most countries) the peasant's bank account, to be sold as cash is needed. This has arisen from two factors: free food handouts (no need to eat animals or to sell them to buy food), and by financing initial livestock for the poor so they can 'farm'. The problem is well illustrated by the fact that marriage dowries in the form of livestock have inflated from a single beast to many beasts.

Whether a peasant who chops a tree for fuel is a greater moron than someone in Hampstead who augments his garden with decking is debatable. What is indisputable is that peasant agriculture is a disaster for the environment, the prosperity of the peasnts involved, and the food supplies of the world.

Joe: there is no universal formula, but commercial farmers are not the main culprits. Most of the areas - including some you mention - are in fact sparsely populated. Commercial farmers are in business to satisfy demands of consumers, not themselves. And they have massive capital tied up with a vested interest in long term sustainabilty.EG You only have to look around the British Isles to see that it is the great estates which have the most woodland, the cleanest rivers and the best-preserved landscapes. If you are the 10th duke, you have a great interest in preserving it for the 20th duke. May not be politically correct, but then few facts/realities are. Furthermore, economic forces tend to eliminate peasant most quickly agriculture where population density is greatest: probably a reflection of the need for greater yields/efficiency to feed the population.

Africa is a sparsely populated continent, with relatively little commercially farmed land, but a by-word for degraded land and destruction of forest and habitats caused by peasants, corrupt governments, and ill-conceived NGOs.

WE have to face the fact that, as in England during the C19th, there is nothing but poverty and misery in peasant agriculture. It is not a bucolic paradise of self-sufficiency, but a miserable and short existence for the humans and a disaster for the environment.

Posted By: funcrusherCommercial farmers are in business to satisfy demands of consumers, not themselves. And they have massive capital tied up with a vested interest in long term sustainabilty.

I'm sorry, but as regards the Amazon Basin, that's plain wrong. Huge, huge areas are being felled right now to grow soya for export, with no thought whatsoever given to replanting or sustainability. It's not for subsistence farming, it's powerful, greedy men, who want as big an area as possible growing cash crops and to hell with the peasants.
I don't personally have any great reverence for small-scale, self-sufficient farming. To some extent I think that self-sufficiency is a bit bogus, in that some things plainly grow a lot better in some places and not others, even though those places might be close together. For example, why should I grow my own wheat here in West Wales, when it would grow so much better a bit further east?
My point is not that subsistence farming is a good thing in itself; it's that right now, it's not subsistence farming that's driving deforestation, it's global demand for commodities - and that where subsistence farming does cause deforestation, it's not because the farmers are stupid, it's because, through no fault of their own, there are too many of them for the land to sustain.
It could be argued that ultimately it's scientific farming, industry and medicine that causes deforestation, by allowing a hugely increased world population.

Well, absolutely. It's consumer demand that uses up resources, and us western consumers consume vastly more resources than subsistence farmers. Commercial farmers and big logging companies are responsible for the overwhelming majority of global deforestation, and as you rightly say, they're only doing what we ask them to.