Skip to Content.
Sympa Menu

permaculture - Re: [permaculture] Earthships

permaculture@lists.ibiblio.org

Subject: permaculture

List archive

Chronological Thread  
  • From: Scott Vlaun <scott@moosepondarts.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] Earthships
  • Date: Wed, 3 Aug 2016 23:04:50 -0400

I have to agree with Toby here. I cut lots of firewood and some timber from
both wide open areas that were cut hard before I bought them 20 years ago,
and from under deep canopy in forest that hasn't been touched in 70 or more
years. A 15 year old red maple and a 50 year old red maple might both achieve
the same diameter, in this case around 8 inches or so at breast height. When
I burn the dry wood I really can't tell the difference. The one from the open
woodlot has simply stored a lot more energy. Ditto on eastern white pine
timbers where growth rings can range from under a mm to 5 mm. When we are
moving the around the are all pretty close in weight and I assume carbon
sequestered per volume.

Scott Vlaun
Center for an Ecology-Based Economy 207 520 0575

> On Jul 31, 2016, at 4:08 PM, Toby Hemenway <toby@patternliteracy.com> wrote:
>
> (Pardon me for geeking out on this subject; I love these sorts of
> theory-meets-practice discussions; don’t really care about who is “right”
> or “wrong,” it’s more about getting the thinking done.)
>
> Ossie at al.—
>
> I totally agree that the fast-growing crap that is bred by timber companies
> is far less dense than old growth. No argument there. But I’m talking about
> real trees in real forests. Now, I’m sure there are plenty of data on rates
> of carbon sequestering under various conditions, and if my internet
> connection weren’t painfully slow these days, I would spend the time to
> look it up, but for now, I will use my experience as a geneticist,
> woodcutter, and botanist to guide my thinking.
>
> I lived for 35 years in timber country and wonderful forests, and spent 20
> years as a geneticist. I’ve had fascinating discussions with timber company
> scientists, and they breed their trees just as Tyson breeds their chickens:
> to put on lots of low-quality material very fast, and then die at a young
> age. So you can’t compare the fluffy growth of those highly bred industrial
> trees with real trees.
>
> Having thought more about it (thanks, Ossie!), it’s not really about young
> versus old trees. It’s about light. It’s a simple matter of physics that
> trees that get more light, and thus more energy, will sequester more carbon
> than trees in a closed canopy. If it were about age, there would have to
> be two different growth systems for the same tree, a low-sequestering phase
> during youth, and a high-sequestering phase at older age. And that’s
> unlikely.
>
> Given two trees of the same species, if one gets more light (and thus
> energy) than the other, it will sequester more carbon per year than one
> that gets less light. The growth rings will have similar density, but the
> high-light tree will have fatter growth rings and thus contain more carbon.
>
>
> This isn’t just theory, it’s been my experience. Having used wood heat for
> 15 years, I have cut many trees, mostly young ones, of many species:
> lodgepole and ponderosa pine, Douglas and grand fir, Arbutus, walnut, oak,
> apple, cherry, alder, eucalyptus, and several others. The young trees
> contained very dense wood, no less dense than the wood in the old trees
> that I have cut. Wood that contained only fat growth rings was no lighter
> when dry than trees with thin rings. So it’s not about the age of the tree.
> Young, fast-grown wood of a “real” tree is pretty close in density to that
> of an older, slow growing tree. Perhaps a bit less dense, but I doubt if
> it’s significant. And if anyone made it through my earlier calculations of
> the area of growth rings at various tree diameters, you know that a thick,
> small-diameter ring can put down far more wood than a thin, large-diameter
> ring. So I’m still thinking that in general, fast-growing trees sequester
> more carbon than slow growing ones.
>
> And what trees are fast-growing? Mostly young ones. In general, young trees
> have better access to light than older ones. It’s simple physics and
> statistics. Even old growth forests have light gaps due to storms, disease,
> insects, etc, and that’s where a lot of wood is being put on. Trees in gaps
> will grow fast. And then there’s fire and large scale blights that leave
> huge areas clear, giving great access to light for all trees over large
> acreages.
>
> I know that this is where the fast growth occurs, because when I look at
> stumps and broken trees in almost any forest, natural or not, the pattern I
> see overwhelmingly is thick growth rings for the first 20-50 years, and
> thin growth rings after that, and I assume that this is because the light
> gap that allowed the trees to get started, whether it was large or small,
> closed after a few decades, slowing growth.
>
> So although young trees have no mechanism that makes them sequester wood
> fast than old ones, young trees as a rule have better access to light, and
> thus are the trees doing the most to sequester carbon.
>
>> Second thing that I would like to mention is that when trees "rot" in
>> forest they do not release all their carbon as CO2 into atmosphere as
>> under such conditions any CO2 released would be heavier than air and
>> therefore unless being technologically shot up into the sky would float
>> under forest canopy
>
> I don’t think this is true. When wood rots, it’s not like it is producing
> dense clouds of heavy CO2 like dry ice (frozen CO2) sublimating into clouds
> of heavy vapor that sink to the earth. The CO2 is released slowly enough to
> be _dissolved_ into the air instantly. It goes into solution and is quickly
> carried away. An analogy: if you dump a cup of sugar into warm water, it
> just sinks to the bottom and stays there as a wet mass (that’s what dry ice
> is doing). If you sprinkle in a small spoonful at a time, it dissolves and
> disappears. That’s what rotting wood is doing. I read an abstract recently
> saying that forest CO2 levels were no higher than average. But it’s true
> that a fair amount of the CO2 released by rotting wood is taken up by
> nearby vegetation; that’s how the CO2 cycle works.
>
> Thanks for the fun opportunity to exercise my brain on this.
>
> Toby
> tobyhemenway.com
>
> Just out: my new book on urban permaculture, The Permaculture City. Order
> it at your favorite bookseller or get a signed copy from me at
> http://tobyhemenway.com/book/the-permaculture-city/
>
>
>> On Jul 31, 2016, at 4:15 AM, ossi@kulma.net wrote:
>>
>> Hi Toby et al.
>>
>> Sorry to tell you, but it seems like you have not explored this issue
>> enough and I suggest you are wrong with the proposed assumption regarding
>> carbon storage in trees. Such growth pattern you describe as universal
>> would apply only on trees grown in cleared open areas, f.e. after a
>> clearcut or as if timber is left in seed-tree positions after harvest.
>> Now if we compare to old growth forests this "universality" does not
>> apply. As an example I have found more than 100 year old spruces grown
>> from total darkness of dense undergrowth so that they are only apx. 15 cm
>> in diameter but when dead seem to be more durable in use than most of the
>> metals I know about. That kind of wood is heavy even if is totally dry.
>> In any of the (semi)natural boreal forests I've seen that "universal"
>> pattern you describe doesn't apply unless it disturbed strongly by human
>> intervention, which equals to collapse in amount of stored carbon.
>>
>> Rate of growth is very simple thing but big growth rings do not relate to
>> with how much carbon is stored in the tree. You can have 3 times fatter
>> tree grown in 15 years, but when you cut that tree down and dry it - it
>> can be lifted with single hand as there is not really carbon stored in
>> their cells, but rather empty space between relatively fragile cell walls
>> and their fresh weight was due to enormous amount of water that was there.
>> Due to large cell structures that kind of fast grown wood doesn't really
>> have any other use than to shade ground for natural forest to regenerate
>> with accumulated density, which stores the carbon for longest periods
>> available.
>>
>> In contemporary Finland current construction wood sales are providing
>> mostly too low quality wood, so that they need to make composite elements
>> out of the wood-material available and therefore it is becoming rare to
>> find single timber being publicly sold as construction wood - as they do
>> not have much of such timber available due to unsustainable forest
>> management which was widely adopted since the 2nd world war. I'd think
>> that old trees that grow slowly have just achieved their adulthood and
>> would likely store at least 1000 times more carbon both in dry weight and
>> durability in time than any fast grown crap from the pulp plantations.
>>
>> So what comes to the forest management practice you describe, yes that is
>> useful in terms of fast supply for timber (which can be stored in
>> buildings for 500 years as you say), but do not relate that to optimal
>> carbon storage of trees as their capacity under such management is not
>> even nearly the optimum that can be achieved. Also in terms of ecology
>> leaving the oldest trees growing should also apply especially if
>> permaculture principles are seriously taken under consideration. I
>> strongly suggest that maths regarding such issues should follow logic like
>> this: more density, more carbon there will be stored and more durable that
>> carbon is within extended periods of time. Of course there is somewhere a
>> point where the growth rate could be too little and cells get fragile due
>> to that, but generally in GOOD quality trees one likely cannot read the
>> growth rings without magnification as they are far less than 0,5 mm.
>>
>> Second thing that I would like to mention is that when trees "rot" in
>> forest they do not release all their carbon as CO2 into atmosphere as
>> under such conditions any CO2 released would be heavier than air and
>> therefore unless being technologically shot up into the sky would float
>> under forest canopy and would be most of the year captured directly at
>> least by conifers or their lichen partners. Also a lot of carbon that
>> was in decomposed wood especially in case of the old growth forest would
>> be circulated by fungi within the system and be either stored in soil or
>> in community of living beings.
>>
>> Now, please keep up the good work you're doing.
>> Thank you for you are and kind wishes for all sentient beings.
>>
>> Ossi Kakko
>> (Eastern Fennoscandia)
>>
>>
>>
>>
>> Toby Hemenway wrote 2016-07-28 06:51:
>>> Scott’s comments are excellent. I would add that the rate at which a
>>> tree sequesters carbon is also dependent on where the other trees are
>>> . Nearly all species of trees slow their growth rate enormously once
>>> the canopy closes as they compete with other trees for light and
>>> nutrients. I’ve looked at tree rings on many species of both hardwoods
>>> and softwoods, and the pattern is universal: fast growth (fat growth
>>> rings) for the first 20-60 years, then only slow growth after that.
>>> They store most of their carbon in youth.
>>> Solution would be to selectively log when the canopy closes to open up
>>> light gaps so the other trees can keep growing fast. Then cut those
>>> when they slow down, and plant new trees in the gaps. Put it all in
>>> structures that last 500 years.
>>
>>>>> On Jul 27, 2016, at 5:53 PM, scott@permaculture.org wrote:
>>>>> In the case of fast maturing trees that are harvested at maturity would
>>>>> be excellent building materials. But trees that are still growing
>>>>> should be allowed to continue to sequester carbon.
>>>>> -------Original Message-------
>>>>> From: Scott Vlaun <scott@moosepondarts.com>
>>>>> To: permaculture <permaculture@lists.ibiblio.org>
>>>>> Subject: Re: [permaculture] Earthships
>>>>> Sent: Jul 27 '16 15:39
>>>>> To Georg's point, sequestering carbon in well built structures made
>>>>> from wood harvested sustainably. Here in Maine there are short lived,
>>>>> fast growing species like balsam and poplar that make decent building
>>>>> materials and would otherwise die and quickly release carbon as they
>>>>> rot in the forest.
>>>>> Scott Vlaun
>>>>> Center for an Ecology-Based Economy 207 520 0575
>>>>>> On Jul 27, 2016, at 5:33 PM, Scott Vlaun <scott@moosepondarts.com>
>>>>>> wrote
>>>>>> My mother in law lives in a 25 year old earthship in NM. I've spent a
>>>>>> lot of time in it and it is pretty fantastic. Can and bottle walls
>>>>>> eliminate a lot of carbon intensive concrete as do massive Adobe
>>>>>> thermal mass walls. The sculptural aspects, especially tile mosaic
>>>>>> make for a very Inspired living space. Embodied energy per sq. ft. on
>>>>>> these structures is extremely low and even in northern NM she gets by
>>>>>> on less than. Cord of wood per year, only needed when cold and cloudy.
>>>>>> I'm extremely sensitive to tire outgassing and have never even gotten
>>>>>> a whit. Labor intensive to be sure though!
>>>>>> To
>>>>>> Scott Vlaun
>>>>>> Center for an Ecology-Based Economy 207 520 0575
>>>>>>> On Jul 27, 2016, at 5:07 PM, Georg Parlow <g.parlow@gmx.at> wrote:
>>>>>>> Thanks Lawrence and Scott for this dialogue. Valuable.
>>>>>>> However, one question, Scott:
>>>>>>>> **Whenever possible eliminate using forest products in construction.
>>>>>>>> The wood is much better used as a carbon sink.
>>>>>>> To my understanding wood IS a carbon sink - and if it sits in my
>>>>>>> house for 200+ years this is just as fine as sitting (and maybe
>>>>>>> falling over and rotting) in the forest. What is it I do not see?
>>>>>>> Georg
>> permaculture mailing list
>> permaculture@lists.ibiblio.org
>> subscribe/unsubscribe|user config|list info:
>> http://lists.ibiblio.org/mailman/listinfo/permaculture
>
>
>
>
>
> permaculture mailing list
> permaculture@lists.ibiblio.org
> subscribe/unsubscribe|user config|list info:
> http://lists.ibiblio.org/mailman/listinfo/permaculture




Archive powered by MHonArc 2.6.24.

Top of Page