Green Building Forum - And now - the African rainforest

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 10:15:34 +0100

http://www.guardian.co.uk/congo/story/0,,2054203,00.html
The world's remaining rainforest is the size of America and is being destroyed at the rate of one Florida a year. When that's gone - no more oxygen.

And now - the African rainforest

biffvernon — Wed, 11 Apr 2007 10:44:51 +0100

And every DIY shed in the land has stuff made of 'hardwood'. Just don't buy it - not even with an FSC sticker - it only encourages them.

And now - the African rainforest

Guest — Wed, 11 Apr 2007 10:59:11 +0100

fostertom, have you seen the self supporting green roof system on roofkrete website and steveleigh posting on the asmet thread.
The answer to disappearing forest has got to be installing this self supporting roof system on the roofs of all our existing housing stock and planting trees as fast as they are felling the rain forest. - and conserving water on the roof.

And now - the African rainforest

biffvernon — Wed, 11 Apr 2007 11:06:10 +0100

Who can have missed the roofkrete and asmet stuff? But somehow I can't see the Baku and other tribes of the African forest embracing the material just yet. The answer to disappearing forest is to stop cutting the trees down.

Meanwhile, if the developers of Roofkrete would donate their secrets to the global commons then, if the stuff is as good as they claim, the world might benefit.

And now - the African rainforest

arthur — Wed, 11 Apr 2007 11:19:55 +0100

Guest, would green roofs on our housing stock help that much?
There seems to be increasing evidence that tree planting in northern areas doesnt' help global warming because it helps absorb solar radiation.
Mirrors on our roofs might be a better option...

And now - the African rainforest

arthur — Wed, 11 Apr 2007 11:48:03 +0100

Posted By: biffvernonAnd every DIY shed in the land has stuff made of 'hardwood'. Just don't buy it - not even with an FSC sticker - it only encourages them.

Is this true? Can you not get softwood sheds?

And now - the African rainforest

WoodYouLikeKent — Wed, 11 Apr 2007 12:02:22 +0100

"Just don't buy it - not even with an FSC sticker - it only encourages them."

As everyone knows (wood manufacturers do): a forest that pays, STAYS.
Meaning: make it worthwhile to be FSC certified (sustained forest/plantations, meaning replanting, reforesting) and we'll all keep our forests (even in Europe!)
Wood for Good:
http://www.woodforgood.com/environment/2tonnesenv.html

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 12:14:27 +0100

Posted By: WoodYouLikeKentmake it worthwhile to be FSC certified

What do you have in mind, to make it worthwhile? Price premium, or what?

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 12:32:52 +0100

Posted By: Guestinstalling this self supporting roof system on the roofs of all our existing housing stock and planting trees as fast as they are felling the rain forest

A great and necessary idea, but not a chance, as stated, unfortunately. Except in the occasional case our existing stock hasn't the structural strength to support such massive, and top-heavy loads. It's something for new-build - let's concentrate on that, for 'extensive' (deep soil, trees etc) green roofs. A better chance for some of the existing stock might be 'intensive' green roofs (thin, light layer of soil, drought-resistant alpines).
For that new-build, maybe ASMET - but even better is use of lots of heavy structural timber - de-barked pine trunks as roof beams etc - to support the weight. Provided it's replanted as soon as cut, the more timber we can incorporate into buildings, the better for the planet. The trick is to take masses of biomass out of the otherwise-inevitable carbon cycle; to sequester as much unoxidised hydrocarbon as possible in permanently warm, dry places so that it doesn't burn, rot, compost itself or otherwise return to dust, which it otherwise would, emitting heat and CO2 and consuming precious oxygen in the process.

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 12:46:38 +0100

Posted By: arthurevidence that tree planting in northern areas doesnt' help global warming because it helps absorb solar radiation

Absorbs solar radiation yes but much/most (what %age?) of that radiation doesn't go to warm the environment up; it's soaked up without temperature rise by powering the endothermic reaction (i.e. a reaction that doesn't happen without external energy input) of converting atmospheric CO2 and ground H2O into CH.... hydrocarbons (wood), emitting O2 as 'waste'. So the more of that kind of solar absorbtion, the better. The rest of the solar radiation that trees absorb does indeed warm up the environment, daytime, but every bit of that energy (and more) is re-emitted to the night sky. It's possibly true that more trees increases the mean equilibrium temperature at the earth's surface, at which that nett-loss energy transaction occurs.

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 12:51:41 +0100

Every tree is a huge solar collector, neatly providing inter-seasonal storage (as wood fuel) of all that it collects, making our manufactured solar panels seem puny. A temperate forest tree has 4 acres of collector (leaf area); however a rainforest giant has 14 acres. That's why the rainforests are so important; homegrown plant-a-tree schemes are no substitute.

And now - the African rainforest

WoodYouLikeKent — Wed, 11 Apr 2007 14:42:37 +0100

Fostertom, why are forest deforests at the moment? To clear space for agriculture, to cut down trees for immediate use. That's not worthwhile for the people 'owning' the forests in the long term, once cut = done with.

FSC, sustainable forestry and plantations = making the keeping of the forest worthwhile. Nothing price premium about it.
Did you know that in the 70's Dutch farmers used 'let-the-fields-lay-empty' European subsidy to plant Oak plantations (leaving the fields empty was against their principles). Now, these plantations are worthwhile for them, for wood manufacturers, for the environment. And FSC certified. Nothing price premium about it. A forest that pays, STAYS.

One Dutch wooden flooring manufacturer even started reforestation in Paraguay even before FSC was born. Forest plantation is now the only forest for miles around.
http://woodyoulike.typepad.com/tips/2007/03/forest_stewarts.html

And now - the African rainforest

arthur — Wed, 11 Apr 2007 15:01:04 +0100

Posted By: fostertom
Posted By: arthurevidence that tree planting in northern areas doesnt' help global warming because it helps absorb solar radiation
Absorbs solar radiation yes but much/most (what %age?) of that radiation doesn't go to warm the environment up; it's soaked up without temperature rise by powering the endothermic reaction (i.e. a reaction that doesn't happen without external energy input) of converting atmospheric CO2 and ground H2O into CH.... hydrocarbons (wood), emitting O2 as 'waste'. So the more of that kind of solar absorbtion, the better. The rest of the solar radiation that trees absorb does indeed warm up the environment, daytime, but every bit of that energy (and more) is re-emitted to the night sky. It's possibly true that more trees increases the mean equilibrium temperature at the earth's surface, at which that nett-loss energy transaction occurs.

I meant the second type of absorption you mention. Why would every bit and more be re-emitted at night? Surely the increase in greenhouse gases is preventing that?
What do you make of this type of report:
http://news.bbc.co.uk/1/hi/sci/tech/6540119.stm
There seem to have been a few of these studies now.

Leaving aside whether or not trees help, wouldn't putting mirrors on everyone's roofs help. Or painting them all white would seem to be a cost-effective measure.

And now - the African rainforest

arthur — Wed, 11 Apr 2007 15:20:50 +0100

oops, I see I'm being a bit stupid. The greenhouse gases work by blocking infrared radiation, not convection like a real greenhouse.

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 16:30:53 +0100

Posted By: arthurgreenhouse gases work by blocking infrared radiation, not convection like a real greenhouse

No, you're right, a real greenhouse works primarily because glass (like the atmosphere) offers little resistance to (is relatively transparent to) incoming high frequency solar radiation (it's high frequency because it emanates from a high temperature source). That radiation warms the flowerpots, worms and spare wellies (and in the case of the atmosphere warms everything on the surface). All those objects then re-radiate everything they've received, but at low frequency (because they're not such a hot source). The glass (and the atmosphere) offer much more resistance to (are relatively opaque to) this would-be outgoing low frequency radiation. Yes, a real greenhouse also blocks convection cooling but that's secondary.

Posted By: arthurWhy would every bit and more be re-emitted at night? Surely the increase in greenhouse gases is preventing that?

Because if the planet was continuously absorbing solar energy but not getting rid of same back into space, it would rapidly get hotter and hotter, like to spontaneous combustion within days. It's more than that - Earth has to get rid of every bit of solar energy it receives *plus* it has to get rid of its own core heat production, otherwise again it would just get hotter and hotter. That's not to deny that we owe our relatively high surface and air temperature to the sun; without the sun the biosphere wouldn't be a biosphere - it would be far too cold for life. But as I say, earth isn't a nett energy absorber, from the sun or anywhere else - it's a nett energy emitter. Daytime it absorbs, night time it emits all of that plus a bit. The greenhouse gas doesn't prevent that; it simply resists it. If that resistance is preventing solar and/or core heat from getting away, the surface (and the air) warms up, yes. As it warms up it succeeds in emitting more heat, against the resistance. Eventually its temperature rises to the point where it suceeds in emitting exactly as much as the total it's receiving in both solar and core heat - equilibrium has been reached. If there's an increase in greenhouse gasses, they resist a bit more, so the surface (and air) temperature rises a bit more too, until a new equilibrium is established at a higher level. That's climate change for you.

PS Arthur, you have to click the html button at the bottom if you want to use the quoting facility. If you click the Edit button on your post, you can do that even now.

And now - the African rainforest

biffvernon — Wed, 11 Apr 2007 18:15:00 +0100

Posted By: fostertom a real greenhouse also blocks convection cooling but that's secondary.

One hates to disagree, but, no. Convection blocking is much more important for a glasshouse.

And now - the African rainforest

fostertom — Wed, 11 Apr 2007 19:46:35 +0100

Hm, much more important? when there wouldn't be any convection to block, if the greenhouse effect hadn't done its thing in the first place? when vents and doors have to be opened in high summer to create enough convection to moderate the greenhouse-effect-created heat?

And now - the African rainforest

biffvernon — Wed, 11 Apr 2007 21:05:32 +0100

You've said it. Open the doors and vents to alow convection and the glasshouse cools down. The glass is still there between soil and sky but is not having much effect now.

And now - the African rainforest

arthur — Thu, 12 Apr 2007 12:07:44 +0100

Wikipedia says that its possible to prove that its mainly convection blocking that's important to a real greenhouse by building one out of rock-salt which doesn't block IR like glass does.
http://en.wikipedia.org/wiki/Greenhouse_effect#Real_greenhouses

So, is there no way of reflecting incoming solar radiation back in a similar high frequencey form so it doesn't get absorbed by the greenhouse gases? Wouldn't conventional mirrors or uv mirrors on roofs help? All the wacky US plans seem to involve putting things up to block the incoming radiation in space but wouldn't it be better to do it on earth?

And now - the African rainforest

fostertom — Thu, 12 Apr 2007 14:46:06 +0100

Good link, I stand corrected. Does this make a difference? - I'm thinking. I suppose same applies to insolation through windows; coated glass though makes the 'greenhouse effect' more prominent.

Posted By: arthuris there no way of reflecting incoming solar radiation back in a similar high frequencey form so it doesn't get absorbed by the greenhouse gases? Wouldn't conventional mirrors or uv mirrors on roofs help?

I guess that would indeed preserve the reflected radiation at same frequency as the incident radiation - anyone know? But - what proportion of the planet's surface would need to be covered with tinfoil, to make a difference?!

Posted By: arthurso it doesn't get absorbed by the greenhouse gases

Do the greenhouses gasses do their resisting of would-be outgoing radiation by absorbtion, or by reflection? I guess the latter, otherwise the upper atmosphere would be extremely hot! - anyone know?

PS Arthur, on the other hand you have to click the Text button at the bottom if you want to make your links 'live' - you can't quote and link properly in the same post, unfortunately.

And now - the African rainforest

arthur — Thu, 12 Apr 2007 15:21:30 +0100

A global effort to mirror roofs might make some difference perhaps? More than green roofing perhaps (although i accept there are other benefits to green roofs). And perhaps cheaper than plans of launching things into space. Painting white, as they do in hot countries anyway, would be cheaper but I don't know if it would reflect at the same wavelength.

Mirrors would probably screw up global satelite communications!

And now - the African rainforest

arthur — Thu, 12 Apr 2007 15:30:50 +0100

Posted By: fostertomGood link, I stand corrected. Does this make a difference? - I'm thinking. I suppose same applies to insolation through windows; coated glass though makes the 'greenhouse effect' more prominent.

Doesn't really make much difference - except it explains why, as you say, the earth releases heat at night, whereas a real greenhouse retains heat at night (to the best of the limited insulating ability of glass) and it implies that a good way of avoiding excessive atmospheric "greenhouse" effect might be, as I suggest, transmitting heat back through the atmosphere at short wavelengths, e.g. by reflection.

Maybe if we had a few more Sahara size deserts then the earth would reflect enough energy to counteract the increase in greenhouse gases.

Sorry about the quoting/linking errors - i'll get the hang of it!

And now - the African rainforest

fostertom — Thu, 12 Apr 2007 16:00:01 +0100

Posted By: fostertomearth isn't a nett energy absorber, from the sun or anywhere else - it's a nett energy emitter. Daytime it absorbs, night time it emits all of that plus a bit

Mind you, it's not as direct and instant as that.
Heat is absorbed daytime and may then take part in all sorts of processes - climatic, chemical, biological etc. It may get turned into other forms of energy than heat. In these ways it may get stored for long periods - seasons or millenia. But eventually, at different timescales, it turns back to a form of energy, mainly heat, that can be, and is, re-radiated, plus a bit. But what's re-radiated tonight, from whatever source, process or timescale, pretty well equals what was absorbed today.
Principal fluctuations in this principle:
Seasonal - there's an absorbtion gain - maybe a total nett gain - in energy absorbed over the summer, but this is matched by an even larger emission loss - certainly a nett loss - in energy lost over the winter.
Polar - there's permanent high absorbtion gain - maybe a permanent nett gain - in energy absorbed in the tropics but this is matched by an even larger emission loss - certainly a nett loss - in energy lost from the polar regions. Energy is transferred by various means, mainly ocean currents and winds, from the tropics to the poles. That's how weather happens.

And now - the African rainforest

biffvernon — Thu, 12 Apr 2007 18:20:12 +0100

Posted By: arthurMaybe if we had a few more Sahara size deserts then the earth would reflect enough energy to counteract the increase in greenhouse gases.

Dont speak too soon. Global warming may get rid of the low-albedo rainforests and replace them with nice new shiny deserts. That's Gaia's way of kicking us off the planet before restoring equilibrium.

And now - the African rainforest

Paul_B — Thu, 12 Apr 2007 19:03:21 +0100

I am getting more confused. Near the begining of this thread Biff stated not to buy hardwood even FSC but I am not sure I understand why. Should I buy softwood knowing it will have rotted in 5-10 years? Should I buy metal which has high production energy implications? Should I use plastic same high energy issues? Or should I not buy anything and have a "low" quality of life?

I was thinking this summer of buying a rocking seat for the garden to spend time outside watching the world go buy rather than the TV. But now I am just starting to feel guilty.

And now - the African rainforest

biffvernon — Thu, 12 Apr 2007 20:54:50 +0100

Guide to the confused:

When I said "DIY shed", I meant the big builders merchants not the sort of thing you have in your back garden.

In such stores, 'hardwood' almost always refers to a tropical timber not a European hardwood. I would encourage the use of our local timbers as that improves the value and good management of our woodlands.

The FSC scheme may be paved with good intentions, but when it comes to tropical timbers there are just too many bad practices and corruption to allow confidence that using this wood is a good idea.

You are right to be wary of buying metals and plastics. In fact it's best to buy as little stuff as possible. But this does not equate with a low quality of life. Go for quality not quantity. String quartets and good company are not resource intensive.

Spend some time to make your own rocking seat out of oak or ash or some such sustainably grown timber. You will enjoy sitting on it far more than if were made of teak and everytime you rested you were reminded of the destruction of the tiger's home.

And now - the African rainforest

Paul_B — Thu, 12 Apr 2007 21:32:53 +0100

Biff,

Thanks for the feedback. My woodwork skills, well lets just say I wouldn't want to put my weight on anything I had made! I'll stick with basic DIY, plumbing and electrics.

Seriously, where do I start to look for local wood products? How can I make sure it is English / European wood? Are European hardwoods Oak, Ash, Redwood? What about birch (seems to be loads in the Sussex and Kent area), beech and anything else I might have missed

And now - the African rainforest

biffvernon — Thu, 12 Apr 2007 22:54:46 +0100

Woodwork skills? We all start somewhere.

A sawmill, perhaps a small forestry estate mill, is often a better source of timber than a timber merchant.

Oak is either American oak (in which case it's American - more oak miles and not as durable) or it's European and there really isn't much to choose between British and French/Polish/Hungarian in terms of quality. Redwood is not a hardwood - it's larch, Douglas fir or Scott's Pine and might be British or Scandinavian. Ash, Beech and Birch will be local. Not quite so durable - best to bring your rocker in for the winter. Ash and beech are stronger than birch, so better for the rocker.

And now - the African rainforest

Paul_B — Fri, 13 Apr 2007 08:33:11 +0100

Many thanks Biff