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Arapiles,
Woops. Sorry about confusing your comment to Roman. I got a little touchy there...
Regarding:
"I actually think that there's a flaw in the article I referenced - they seem to presume that a growing tree takes up CO2 as quickly as it's released by burning another tree ... But if a tree takes 20 years to sequester X grams of CO2, it will presumably take another tree 20 years to sequester the same amount of CO2 released in one hit by burning the first tree."
Yes, that's exactly how I read it, too. That's what I meant by 'in theory' versus 'in practice' though I didn't go into the detail that you did. I don't, however, think that the author overlooked the growing time of trees. He mentions exactly the same thing you just said, and it is sort of the entire basis for his argument against wood as a 'carbon-neutral' alternative fuel source. He wrote:
"But what happens when trees are cut and burned faster than they are replenished? If a forest is being harvested for fuel at a rate of 1000 trees (or cords, or tons, or acres, pick your unit) per year, but less than 1000 units per year are regnerated via regrowth, then carbon is being dumped into the atmosphere faster (by burning) than is being removed (by tree growth)."
I would agree, certainly human society should not change to wood en-mass, since we'd strip the planet bare in about thirty seconds.
Though I agree with the article you cited (I had better, since it actually supports MY position) a big point against its validity is this: it isn't a scientific paper, any more than the other four articles that I googled are. It is a post on a forum, just like this thing that I am typing now. Who is this guy? What are his credentials? (He may have good ones, but I can't find them.) I agree with what he is saying but I'm just a layman, too, albeit a highly educated one. This is a basic problem with the internet as an information source: any idiot can post whatever he wants (me included) and it is difficult to separate the wheat from the chaff. You have to actually read it all with a critical eye. This is what I meant by saying that google-based arguments are void, because by that standard wood fuel is the solution to all our problems, since 4 out of 5 google articles say so.
The Wilson Center paper on ethanol use that I cited, on the other hand, is a rigorous scientific paper published in a peer-reviewed journal. I haven't found a similar paper about wood fuels, but I'll keep my eye out.
Anyway, the exact same argument that your article makes against wood can be made against alcohol, since you have to wait for the plants that the alcohol is made from to grow back, too. Of course plants like corn, sugar cane, and switchgrass all grow back in one season or less. But the fossil fuels currently used to produce, process, and ship alcohol still makes it more of a losing proposition (carbon-wise) than wood used on a SMALL scale. (In all honesty, the twigs and pine cones that I burn in my Kelly Kettle grow back in one season, too, and no-one burned fossil fuels to produce them.)
Consider, again, the post you cited:
"An interesting sidebar to this question is that the cycle time plays a key role in the analysis. If the fuel to be harvested matures quickly (hay or bamboo are good examples), then the cycle time can be measured in a few months or a couple of years, rather than in decades. The fuel can be harvested and burned faster, but the fuel’s energy density, in terms of BTUs per acre of harvest, is much lower. It seems likely that there is some optimal combination of energy density, carbon density and cycle time among the available renewable fuels."
Indeed some of the responses on that forum disagree with the author (though I think all the arguments against him were puerile). The author also, in a response on the forum, admits that a well-managed woodlot used as a source of wood fuel WOULD be carbon-neutral.
Certainly more carbon-neutral than burning oil and releasing the CO2 that used to make the entire Earth a boiling hothouse before the Azolla event. (See my reference a few posts ago. It's actually very interesting.)
But I will admit that my net take is this: I think the difference between alcohol and wood on the small scale that we campers use is trivial, and in fact the difference between alcohol and gas is trivial, too, on that small scale. One isopropane canister is a drop in the bucket compared to all the other carbon an individual generates. So, ignoring the weight savings, we should all have no real problem with using gas stoves.
(Some stuff edited out because this is too long already.)
By the way, I honestly thought that Brazil was the only country with a truly dedicated ethanol infrastructure, yet you described distillation points very close to the cane fields in Australia. Are you sure those aren't just the boilers for reducing the cane to syrup? Or did Australia build these facilities recently? Or are they just very small-scale? Or am I just ignorant? (Which wouldn't be surprising, since I am an American...)
Edited by acrosome on 03/25/2008 02:46:28 MDT.
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