From Duke University and the Department of Obvious Science comes this study partially funded by NASA:
Standing trees better than burning ones for carbon neutrality
DURHAM, N.C. — The search for alternatives to fossil fuels has prompted growing interest in the use of wood, harvested directly from forests, as a carbon-neutral energy source.
But a new study by researchers at Duke and Oregon State universities finds that leaving forests intact so they can continue to store carbon dioxide and keep it from re-entering the atmosphere will do more to curb climate change over the next century than cutting and burning their wood as fuel.
“Substituting woody bioenergy for fossil fuels isn’t an effective method for climate change mitigation,” said Stephen R. Mitchell, a research scientist at Duke’s Nicholas School of the Environment. Wood stores only about half the amount of carbon-created energy as an equivalent amount of fossil fuels, he explained, so you have to burn more of it to produce as much energy.
“In most cases, it would take more than 100 years for the amount of energy substituted to equal the amount of carbon storage achieved if we just let the forests grow and not harvest them at all,” he said.
Mitchell is lead author of the study published in the peer-reviewed journal Global Change Biology Bioenergy. Mark E. Harmon and Kari E. O’Connell of Oregon State University co-authored the study.
Using an ecosystem simulation model developed at Oregon State, the team calculated how long it would take to repay the carbon debt – the net reduction in carbon storage – incurred by harvesting forests for wood energy under a variety of different scenarios.
Their model accounted for a broad range of harvesting practices, ecosystem characteristics and land-use histories. It also took into account varying bioenergy conversion efficiencies, which measure the amount of energy that woody biomass gives off using different energy-generating technologies.
“Few of our combinations achieved carbon sequestration parity in less than 100 years, even when we set the bioenergy conversion factor at near-maximal levels,” Harmon said. Because wood stores less carbon-created energy than fossil fuels, you have to harvest, transport and burn more of it to produce as much energy. This extra activity produces additional carbon emissions.
“These emissions must be offset if forest bioenergy is to be used without adding to atmospheric carbon dioxide concentrations in the near-term,” he said.
Performing partial harvests at a medium to low frequency – every 50 to 100 years or so – could be an effective strategy, O’Connell noted, but would generate less bioenergy.
“It’s a Catch-22,” she said. “Less intensive methods of harvesting release fewer emissions but yield less energy. The most intensive methods, such as clear-cutting, produce more energy but also release more carbon back into the atmosphere, prolonging the time required to achieve carbon sequestration parity.”
Given current economic realities and the increasing worldwide demand for forest products and land for agriculture, it’s unlikely that many forests will be managed in coming years solely for carbon storage, Mitchell said, but that makes it all the more critical that scientists, resource managers and policymakers work together to maximize the carbon storage potential of the remaining stands.
“The take-home message of our study is that managing forests for maximal carbon storage can yield appreciable, and highly predictable, carbon mitigation benefits within the coming century,” Mitchell said. “Harvesting forests for bioenergy production would require such a long time scale to yield net benefits that it is unlikely to be an effective avenue for climate-change mitigation.”
The research was funded by a NASA New Investigator Program grant to Kari O’Connell, by the H.J. Andrews Long-term Ecological Research Program, and by the Kay and Ward Richardson Endowment.
Don’t crow too loudly, good people. Twenty years in Asia has taught me that when someone of influence or authority starts spouting an inane concept, you are about to get your pocket picked or your freedoms curtailed. I’m now old enough to realize that rule has always applied in the rest of the world, too.
Forests in Australia which have been harvested for hundreds of years and have received international awards for the quality of their management are now being locked up by ‘mindless green doctrine’. These are gradually becoming locked up areas where no-one can go. This is happening all over the world.
The above mentioned publication is simply another small part of that campaign.
This timber which would have been sequestered in buildings and other structures will now be left to stand, until, inevitably, it WILL burn.
Indegar says it all in this comment:
indegar: May 31, 2012 at 4:50 pm
I also theorize a major motivation for manufacturing and resource producing countries to encourage ‘green doctrine’ in emerging economies is as a form of economic hegemony. They really don’t want the competition.
Locking up land as ‘national forests/parks’ locks up forestry products, but also locks up good farming country, mineral wealth, potential water catchment schemes, etc.
Witness Brazil ignoring the pressure and now being one of the world’s greatest exporters of corn, soyabean, and beef.
I think we may need the food more than we need the forests, and there is great potential for the greening of cities and semi rural areas.
“””””……wobble says:
May 31, 2012 at 7:27 pm
George E. Smith; says:
May 31, 2012 at 7:12 pm
Juvenile growing forests are a carbon sink; old growth forests are not; they are carbon neutral, so they don’t do a thing for the CO2 balance.
Old growth forests store carbon. If you lose the old growth forest, then you lose the storage. That most certainly affects the CO2 balance…….”””””
I started to write a response to this post. Then I decided it simply wasn’t worth wasting my time on.
OLD GROWTH FORESTS ARE CARBON NEUTRAL. They die and rot, and return to carboniferous gases, as fast as they convert CO2 into new wood. They are in a state of dynamic Equilibrium. Well they are until a forest fire returns much of the carbon back into atmospheric CO2.
I’m not against preserving old growth forests; but they DO NOT sequester carbon; only actively growing young farmed forests do that.
Rob L says:
May 31, 2012 at 2:40 pm
If CAGW were a real problem then one of the easiest solutions would be to bulldoze and bury large tracks of forests. Quick, effective, but anaethema to the green movement.
—————————
Too much added pollution from a bulldozer. Unless you use an electric powered bulldozer. That should be ok.
Well, yeah – but burning wood keeps me warm in the winter. I have tons of standing trees – and harvest them as I need them – while replacing them at the same time. Mother nature is wonderful.
Dave Worley says:
May 31, 2012 at 8:14 pm
That’s a myth.
Consider the volume of wood created in an old tree versus a young tree, each year, i.e. a tree ring. In an old tree, the new wood is at a much bigger diameter than the young tree. Now integrate the whole surface. Really, this isn’t hard, is it?
Where we would agree is an old SICK tree doesn’t sequester much carbon.
markx says:
May 31, 2012 at 9:18 pm
Yes. i Believe that is the actual intent of this. Oregon has a mixed population, but like many areas in America, the urban population drives the votes. While the rural populations are mixed politically, the university towns and capital cities are often overwhelmingly liberal, to the point that science is a political beast. These cities simply outvote normalcy in favor of bizarre political theory because of the monolithic nature of the voting populace. Studies such as this are publicity pieces to ensnare bureaucrats and politicians into forcing the will of these nut cases on the world.
This actually leads to the unexpected position that we should clearcut absolutely everywhere to allow the vastly more effective carbon scrubbing of young trees. While simultaneously turning all of the trees we just cut into something more permanent stored far away from the termites that naturally and organically release the carbon dioxide otherwise.
That is: You can do substantial carbon sequestration by turning the trees into houses.
That’s great. You’re claiming that they are in Equilibrium. This means that they are continuing to store carbon.
They don’t do a thing for the CO2 balance as long as they’re NOT harvested and burned. Because, if they are harvested and burned, then they most certainly do something for the CO2 balance. Even if they are harvested and left to rot, then they most certainly do something for the CO2 balance.
wobble: May 31, 2012 at 11:39 pm
Said: “That’s great. You’re claiming that they are in Equilibrium. This means that they are continuing to store carbon.”
It seems to me a straightforward enough concept.
If old forests are left untouched, there you have a finite amount of carbon sequestered. (Give or take the odd spike of forest fires). Seems a little pointless, except to sandal wearing hippies who presumably ‘feel good about it’ knowing it’s there, even though they may not be allowed to visit.
Manage and harvest forests, lock up that carbon in construction, plant young forests or let harvested ones regenerate, and you can, through skilled management, continue increase the amount of sequestered carbon.
You can argue it will eventually find its way back into ‘the system’, and that is true in all cases, it just depends on the timescale you prefer to discuss.
Title correction:
“Who would have thunk it? Standing trees better than burning ones” should read:
“Who would NOT have thunk it? Standing trees better than burning ones”
Is my English OK?
Markx says “it just depends on the timescale you prefer to discuss”.
Correct. From the vast forested areas all over the globe when human population was tiny, how many man-made wood structures remain? It’s so small a % that it’s not even worth calculation. So it’s not helpful to promote schemes that tie up CO2 ‘for the moment’ because in the long run, the wood essentially decays back to GHG. I can find no evidence that the carbon content of the global soil is increasing, so soil is not a sink either.
People should be objecting to green get rich schemes that allow carbon credits for biomass accumulation of C. It will all revert to GHG one day (unless it forms coal or the like). It’s just a way to take tax $ from your pocket and give them to people with con-man dreams deviod of scientific merit. If you get paid to increase the carbon content above a certain area of land by any biomass method, you should pledge to return the money if and when the stored carbon falls. Also, it usually will fall unless you actively spend $ to manage the increase.
Relatedly, there is a current misconception in Australia today that GHG reduction will be achieved by dehydration of abundant brown coal before large scale combustion in conventional fossil fuel electricity stations. Sorry, the equation does not work like that. Each atom of carbon has the ability (when combined into compounds, or as high carbon coal) to produce a certain amount of heat before grabbing a couple of oxygen atoms to make CO2. It does not matter if the coal is wet or dry, except that it costs more money to dry and less money to transport. Sometimes the $ cost balance is positive, sometimes negative, depends on the case. But don’t kid youself that you have produced a better, ‘kinder’ product than natural high carbon black coal.
For biomass to burn it is hard to beat the eucalyptus, for tonnage per hectare see
http://news.mongabay.com/2009/0717-forest_carbon.html
plus the advantage that they regenerate when cut, from the stump or when one or more of multi-stem tree trunks are cut, so the living root systems ensure quick regrowth.
I have gathered ~8 tons a year from 1 hectare for thirty years mostly dead wind blown or drought stricken trunks and have far more tonnage on the property than when I came here and not a tree destroyed. 110 years ago there were only tree stumps visible for miles as steam powered mining took all available timber according to an old resident in the 70’s, now these stumps are trees up to 3′ diameter, most multiple trunks from around waist height up.
Of course CO2 sequestering is a futile exercise, but I do like to be self sufficient and still see an increase in a natural resource.
Geoff Sherrington says:
June 1, 2012 at 12:57 am
“From the vast forested areas all over the globe when human population was tiny, how many man-made wood structures remain?”
I’m not sure how accurate this is, or the timescale references: • http://www.rain-tree.com/facts.htm
Geoff Sherrington says:
June 1, 2012 at 12:57 am
“From the vast forested areas all over the globe when human population was tiny, how many man-made wood structures remain?”
I’m not sure how accurate this is, or the timescale references: • http://www.rain-tree.com/facts.htm
We have only lost 57%? I’d have thought far more!
Geoff Sherrington says: June 1, 2012 at 12:57 am
“….it’s not helpful to promote schemes that tie up CO2 ‘for the moment’ because in the long run, the wood essentially decays back to GHG….”
I’d like to emphasize the point this applies equally to standing forests AND to manmade structures,
I am strongly of the opinion forests should be managed and utilized, and believe that can be done without detrimental effects to the environment, and that most likely it will have beneficial effects.
If locking up carbon counts for anything – and that’s a debatable point – then it’s surely much better to covert it into building material etc. where it can remain ‘asleep’ for centuries than to set fire to it within months. That way the forest remains vigorous and thus soaks up more atmospheric CO2 ; a moribund woodland stand is of little value.
Can I get a grant to study the obvious?
To Duke: Are you smarter than a fifth grader.
Nope.
basically…..who cares
We’re talking about 150 parts per MILLION….and almost all of that we had nothing to do with
Hey, I just invented this thing called the wheel, I bet if we use to roll stuff on it will save energy. I also just invented the ax which we can use to cut down trees to make wheels.
If you ever were really going to use trees for carbon sequestering, a potentially economically viable method worth trying regardless is using them to make Biochar. The wood is subjected to pyrolysis, heating in a low/no oxygen environment, in modern industrial plants by varying the temperatures they can get varying yields of bio-oil, char, and burnable syngas, and produce 3-9 times the energy consumed, which can be financially beneficial.
Then instead of burning the biochar (aka charcoal), use it traditionally, break it up into small pieces and incorporate it into farmland. which will become a rich terra preta soil. It increases the fertility of the soil, reduces the need for chemical fertilizers, retains water reducing irrigation demands, etc. Depending on how much is used and how deeply it’s mixed into the soil, it might just be a one-time application. If it’s shown to work with modern farming techniques and can be mixed in easily (perhaps merely spreading while tilling) then it becomes an investment for farmers that’ll save money later, worth paying for.
Without government mandates and money, you can conceivably have economically sustainable carbon sequestration, although that aspect doesn’t need mentioning, that reduces the need of fossil fuels to run irrigation pumps, farm equipment for fertilizer dispensing, as feedstocks for fertilizer production, etc. There are very good reasons to try this, without ever resorting to “global warming mitigation” as one of them.
William McClenney says:
May 31, 2012 at 8:44 pm
Meanwhile, back at the ranch, Tonto, cleverly disguised as a forest …
http://en.wikipedia.org/wiki/Tonto_National_Forest
How is it that some believe that conifer forests will actively grow forever? Even trees get old, they get weak, and they often succomb to disease and destructive insects. That is if they don’t burn before they reach the end of their viability.
Fire is part of the reproductive process of conifers. If we don’t harvest them, they will eventually burn. If the amount of fuel in the forest has been artificially kept high through anthropogenic fire suppression, you’ll likely end up with something like a firestorm beyond our control at higher temperatures that have more negative long-term effects.
You can either harvest the timber or let nature have its way, but you can’t expect an endless trend of “carbon sequestration”.
Mitchell’s take home message “is that managing forests for maximal carbon storage can yield appreciable, and highly predictable, carbon mitigation benefits within the coming century,” “Harvesting forests for bioenergy production would require such a long time scale to yield net benefits that it is unlikely to be an effective avenue for climate-change mitigation.”
His message is basically WRONG for tropical and sub-tropical evergreen forests.
Proper management and harvest of such forests can completely reverse the last century and a half accumulation of excess atmospheric CO2!
See:
“Irrigated afforestation of the Sahara and Australian Outback to end global warming”
http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s10584-009-9626-y
“Replacing coal with wood: sustainable, eco-neutral, conservation harvest of natural tree-fall in old-growth forests”
http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s10584-009-9625-z
and
“Irrigated Afforestation of Deserts to Thermostat the Earth, End Global Warming
and Provide Enormous Sustainable Sources of Wood to Replace Non-renewable
Fossil Fuels”
http://www.pipeline.com/~lenornst/ThermostatingTheEarth.pdf