How did my carbon credit end up in your kiln?

Is wood firing green?

The answer to this question has always been obvious to me. No. Laughably no.

I got a rude awakening this last week to find I may be the only one that fires with wood outside of Japanese firers in Japan that feels this way.

My blog post of about a week ago has provoked a lot of discussion on a couple of ceramics lists in the U.S. and Australia.  The reactions I read inspired me to take on a project to research just that question. How much carbon does wood firing put out compared to other types of firing. What are the possible effects of taking  as much wood as it takes to get a kiln up to temperature out of the natural cycle and how does that effect what would happen naturally? I have a list of other questions, about 1/2 of which I have found answers to. I am purposefully avoiding studies that have a political slant. I am trying to stick with studies that are neutral on politics.

That seems to be the crux of the problem. Politics. It has been strongly suggested I have an agenda to paint wood firing as an un-green activity. I didn’t realize it needed any painting.  If I am truthful I will say I actually don’t care where the data falls. It is numbers. Not political.

An important question would be ‘Why would I want to go to the trouble to denigrate wood firing?’ I am spending many hours that would be better spent getting my WOOD FIRED work out there. .

My research hasn’t answered some of the comparative questions yet but I have been able to conclude a wood firing throws out 1/2 the weight of the wood burned into the air in the form of CO2. In a very short time frame. All the mental gymnastics about methane production, small and large particulates, etc. are irrelevant. I have also been able to answer some of the aspects of the question-What would happen to that wood if it is downed and left in the forest?

For a geek like me the following from a study is very interesting.

Although translocation of organic matter from woody litter to soil can occur via soil fauna as well, DOM (dissolved organic matter) is recognized as one of the major forms for mobilization of C (carbon) and N from the forest floor to the mineral sol

(Qualls et al. 1991;Yano et al. 2005)

Previous studies have found that partially decayed organic matter is leached from the wood to the soil underneath becoming part of the soil organic matter (SOM) In the long-term, as mentioned before, residues from lignin decay are building blocks of humus. Hence, we hypothesized that greater and more complex humic substances would accumulate under decaying wood as decomposition progresses.  Taken from the same paper.

This particular study found that a 15 year window would reduce carbon but still leave a significant amount on the forest floor and  in the soil.

A different study found that 26% of the carbon would be dispersed in soil and streams. Hard data?  See Chambersbiogeochemistry.

So, I am not making any friends in the wood firing community but these are the facts.

Here is an example of a reaction I got.

If you want to really go “green”, find all of the
wasted energy in your lifestyle.  If that is too much hardship for you then
stop looking for others to point fingers at.

It has been suggested I am bringing on the negative reactions myself. In my case I never discount that possibility.

I would like to point out this story from the BBC.

Does everybody think that when carbon credits become the norm nobody is going to ask, “How did my carbon credit end up in your kiln?”


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6 Responses to “How did my carbon credit end up in your kiln?”

  1. Lee in Mpls Says:


    A big thing you overlook in wood as fuel, is the carbon
    sequestered in the roots which is release very slowly over time.
    Firing with wood is 2 to 3 times more effective than wind or solar
    power in eliminating the produciton of carbon. 63% of the carbon
    held by a tree is sequestered in its roots.:

    See this article:

    Short quote here:

    As a Global Warming/Greenhouse Gas mitigation strategy, co- firing
    energy crop biomass at existing coal-fired power plants achieves the
    greatest reduction of any renewable energy resource option, where:
    Electricity produced from biomass fuel is carbon cycle neutral —
    just like wind or solar energy.
    However, unlike other renewable energy options, tree energy crop
    biomass also sequesters carbon (a sustainable long-term storing)
    through the trees’ root system.
    Co-firing energy crop biomass fuel in base load power plants directly
    displaces/reduces coal use, which achieves almost two times the
    Green-house gas reduction benefit of placing wind or solar power
    facilities on an intergrated electricity power grid.

    Below ground Carbon Sequestration of Tree Energy Crops: In December
    2001, Common Purpose/University of Florida excavated 14 month old
    whole eucalyptus trees at our Energy Crop Plantation. The trees
    averaged ~20 feet in height, and had ~ 3 inch trunk diameters at their

    The procedure used a Caterpillar back-hoe to excavate whole trees
    including their root system

  2. togeii Says:

    Hello Lee,
    By the way, my name is Dave.
    First of all, your own data says the root mass is 38%, not 63%. Think about having 63% of a tree mass in the roots. Not even baobabs have that. For a more comprehensive look at waste mass see Monitoring and Measuring Wood Carbon. It gives a 50% merchantable figure, the rest is branches, roots, etc. This is consistent with 25% root.

    Take a look at this data.


    Overall, wood fueled biomass power plants emit about 50% more CO2 per MWh than existing coal plants,
    150% more than existing natural gas plants and 330% more than new power plants.

    While beyond the scope of this briefing, additional carbon impacts from wood fueled biomass power plants
    must be added since the forest’s ability to sequester carbon has been reduced through logging. A full
    accounting of carbon dioxide impacts from wood fueled biomass power plants would also include carbon
    emissions from the decay of forest root systems, oxidation of soil organic material as well as the use
    petroleum for logging of forests, chipping the wood, and hauling a large quantity of relatively small fuel
    loads at distances up to 100 miles or more in trucks that get about 5 miles per gallon.

    It is impossible for a biomass power plant that burns existing forests to be carbon neutral since any increase
    in forest cutting negatively affects the current baseline condition of forest growth versus cutting and
    mortality. Furthermore, it is the overall carbon emission input rate into the atmosphere from an energy
    source that matters, because overall carbon sequestration rates can not be expected to increase to make up for
    increased carbon inputs. With biomass burning of existing trees, the overall sequestration rate may even
    decrease because of the impacts on the forest, creating a double whammy.

    You can source the report through a search engine.

    I am sure the Cat used to excavate the roots has a zero carbon input.
    Lee, my goal isn’t to respond to every detail you think up. I am sure you are up to doing a comprehensive research paper. I am in the middle of mine. The data I have is root is on average 25% of mass.
    My point is that the natural cycle is interrupted when the wood is carted off to the kiln. Can you dispute that simple fact? Waste wood, which you like to tout as some kind of panacea, is actually one of the more expensive forms of carbon as it has gone through extensive processing that only adds extra carbon to the equation. You burn it and the extra carbon is added to the total. If it was kept in long term storage, i.e., not burned, it would go through a natural decomposition that lasts far longer.
    The carbon cap and trade is going to factor in processed wood. Do you think “waste” wood is going to be excluded? No, it is part of a total of sums. The only alternative to landfill for “waste” wood isn’t burning by the way.

  3. Philippe Papadimitriou (Switzerland) Says:

    Dear Dave,

    I am a biochemist and my somewhat old knowledge in physics and thermodynamics allows me to tell you you are right.

    Everything that consumes energy (and heat for ceramics is of course energy) produces molecules that are more stable (i.e. having less “inner-energy” systematically providing exogenous energy) as final components. Most of these are small ones, like carbon monoxide or carbon dioxide.
    I guess the presence of these molecules (+ other organic ones – based on carbon, hydrogen, oxygen and nitrogen) is what has led to the common use of the “carbon footprint”.

    NB: All scientists, please forgive me for my poor use of exact terms – my point is really to show a point that everyone can understand here, not to give a full lesson of what is unfortunately partially lost in my mind anyways.

    One more way to accept it is to acknowledge the first use of mankind for fire: heating = recieving energy instead of letting ourselves use our own to keep an appropriate body temparature.

    Then, I have to admit I do not know if wood-firing is more profitable than the use of natural gas as as source of energy (or other methods) to fire ceramics.

    One aspect to maybe investigate is how “human” is the energy produced to end to the same end use (the production of ceramics).
    If a man has to go into the forests, fall trees, cut wood, bring it to the kiln, etc. all by his own (I let each one picture what are all the steps) rather than use machines or any other energy-consuming devices to do most of the whole work, then it may very well be that wood-firing is much better in terms of “bad energy”.
    But if one only considers the firing process, this might get a little more complicated, at least for me.

    I didn’t want to provide an answer, but more to give hints as to where this subject may go now..


  4. togeii Says:

    Hello Phil,
    Thank you. I will take a look at the direction you are going.

  5. Markus Boehm Says:

    Hi David,
    indeed I’m asking myself why you are using such a lot of energy in the try to say wood firing is NOT carbon neutral. I would prefer to fire my kiln.

    I still think the whole discussion lacks in clear terms.

    At first: Wood as carbon neutral fuel
    As mentioned before wood is a (totally) renewable resource and a carbon neutral fuel. It is very easy to see that a tree has taken the CO2 from the atmosphere for it’s growth and this CO2 is released into the atmosphere again when the wood is fired. Not more! And the next tree that takes his place will do the same. So it is a carbon neutral fuel.
    To argue this point you came with the “time frame”. But the time frame is irrelevant as long as the forested area doesn’t change. To give you an example:
    Say I have a forest of 100 trees of every size and age. For this example let us set the time frame to 100 years. I use one tree every year and plant a new one (you can use different numbers but this way it is easy to imagine). After 100 years my grand son will end up with a forest with 100 trees of every age again – the amount of carbon that is stored in his 100-tree forest didn’t change. But this is not only true for the time frame of 100 years. If the forest is constantly used you will always have one tree of 100 years to cut and one that was planted recently and everything in between. And if I look around, this is exactly the situation that we have: In a forest I will always see areas with recently planted trees as well as trees ready for cutting – and everything in between.

    Then you are comparing firing wood with the decay of wood and say: Another problem is the carbon released during decay doesn’t all go into the air.
    This might or might not be true – but it is irrelevant for questioning wood as a carbon neutral fuel. If it is true, then the decay of wood is not carbon neutral – it takes CO2 out of the atmosphere so it would be carbon negative (positive for the environment). So if you compare those two different ways of how wood might end up you can state that it would be better for the climate if the wood stays in the forest but it gives no information about the carbon neutrality of wood as fuel. And if I look around I have to accept that this statement is as wrong as irrelevant. It is irrelevant because the forests are mostly in private ownerships and the owners have to make money from taking trees out and selling them. If somebody would like to change this he would have to change our economy and with that the whole society – nothing that lies within the possibilities of a woodfirer. And it is wrong because the “natural” decay of wood at least in my surrounding doesn’t work the “natural” way without damaging the forest. To give you an example: After the wall came down we were told that only private business works efficiently and following that public opinion the municipality of Mirow rented its forest to a private enterprise. There was an area in the forest 1 km from my property with 25 year old pines standing too close to each other where I have always cut dead trees and used them for woodfiring. But the private enterprise went with a big machine (we call it in Germany “Harvester”) through this forest and took out healthy trees for sale but cut and left the lower quality trees on the ground. Two years later wood worms had attacked the rest of healthy trees in a way that in this part of the forest every tree had to be cut. That is the reason why foresters here are happy about people that take the dead trees out of the forest.

    If the carbon released during decay doesn’t all go into the air then this should not only be true for the wood but also for the other parts of the tree which are constantly produced by a tree: needles and leaves. Wouldn’t that make wood a slightly carbon negative fuel?

    I think that we have to divide clearly what we are discussing: wood as carbon neutral fuel or the environmental impact of woodfiring.
    So: second
    Woodfiring seems not to be carbon neutral since for example we are using chain saws and tractors for cutting and transporting. But on a second view all this becomes complicated: here the farmers use biological grown fuel for their tractors – so how do you measure the carbon footprint for the transport? And here I’m asking myself: why are we discussing these problems? Shouldn’t it enable us to make decisions for making our live at least a bit more sustainable? Your statement that you are firing with wood and that you will keep on doing so no matter what damage (you believe) it does, sounds a bit strange to me. In that sense I asked in my earlier post for a comparison of firing methods – and when you are comparing then you have to take into account that for drilling oil and gas, for mining coal or producing solar panels or wind mills you have to invest also energy for producing and transporting – not to take into account things like Oilwater Horizon.

    So, David, looking at your argumentation I am asking myself if there is a problem not in the data that you are accumulating but in the way that you are interpreting those data.



    European Woodfire Conference
    Markus Boehm

    web :
    fon : +49 (0)39833 22219
    fax : +49 (0)39833 22252
    mob : +49 (0)171 1710799
    snail : Alt Gaarz 6, D-17248 Laerz, Germany


    • togeii Says:

      Hello Markus,
      Thank you for your comment.
      I look forward to your paper framing the questions the way you choose and your interpretation of the data in the way you see fit.

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