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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    •  
      CommentAuthordjh
    • CommentTimeJul 11th 2020
     
    Posted By: tonyFully agree so signed it 🙂

    Ditto, and also forwarded the request. We need to get the signatures up.
    • CommentAuthorCliff Pope
    • CommentTimeJul 12th 2020
     
    "Examine in detail how burning forest/woodland timber releases carbon into the atmosphere which cannot be reabsorbed by new tree planting for many decades"


    I thought the argument was that young trees absorbed CO2 at a faster rate than established woodland, so a managed woodland with a quick turnover had a younger average age of tree, and that this net gain in efficiency could be "spent" on efficient burning, with an overal neutral effect?
  1.  
    We have both signed it.
    • CommentAuthorJonti
    • CommentTimeJul 12th 2020
     
    So if we all move to the city and live in small flats where is all the food coming from? I think the answer is to reduce the energy need down to as low as possible regardless of where you live.

    As for the burning of forests being the problem I believe it is the clearing of large areas of forest (much being illegal) for crop growing and the burning of wood in industrial settings that is the problem rather than burning wood for domestic heating. However, even domestic use should be done at the bare minimum.
    • CommentAuthortony
    • CommentTimeJul 12th 2020
     
    :heart: I love the idea of energy use reduction, it is my number one priority.
  2.  
    >>>Examine in detail how burning forest/woodland timber releases carbon into the atmosphere which cannot be reabsorbed by new tree planting

    The Government has already examined that in great detail:
    https://www.theccc.org.uk/publication/biomass-in-a-low-carbon-economy/

    They concluded that carbon is better left in forests or built into buildings. Waste biomass could be burned but there won't be enough of it so it needs to be prioritised to energy uses with CCS, so not for heating buildings or biofuel in cars.

    I think we need legislative action on the findings, not another review, so while I respect the initiative I didn't sign the petition this time.
      Screenshot_20200711-235810_copy_1209x576.png
  3.  
    Will , thanks for the link
    • CommentAuthorgyrogear
    • CommentTimeJul 12th 2020 edited
     
    Posted By: Cliff Pope"Examine in detail how burning forest/woodland timber releases carbon into the atmosphere which cannot be reabsorbed by new tree planting for many decades"


    The answer is not planting new trees or woodland, but HEMP - Man's most useful plant...

    https://hemp-copenhagen.com/images/Hemp-cph-Carbon-sink.pdf

    ''Industrial hemp has been scientifically proven to absorb more CO2 per hectare than any forest or commercial crop and is therefore the ideal carbon sink. In addition, the CO2 is permanently bonded within the fiber that is used for anything from textiles, to paper and as a building material. It is currently being used by BMW in Germany to replace plastics in car construction. It is therefore additional to what would otherwise be grown or sourced from oil. It can be constantly replanted and as such meets permanence criteria as defined by the Kyoto Protocol."

    gg
  4.  
    However like most of us on this forum you rather live in a area with lots of green plants instead of living a green lifestyle.....

    I'd imagine most people on this forum are doing both, or in the process of doing so (in my case at least).
    •  
      CommentAuthorfostertom
    • CommentTimeJul 13th 2020 edited
     
    Posted By: gyrogearthe CO2 is permanently bonded within the fiber
    All that means is that hemp fibre is relatively slow to rot when exposed to rotting conditions like wet - but rot it will, soon enough to embaras CO2 levels in the forthcoming critical period. Any plant fibre, if kept in rot-free conditions, like an unleaky building fabric/interior, remains 'permanently bonded' - until it isn't.
    •  
      CommentAuthordjh
    • CommentTimeJul 13th 2020
     
    Posted By: fostertom
    Posted By: gyrogearthe CO2 is permanently bonded within the fiber
    All that means is that hemp fibre is relatively slow to rot when exposed to rotting conditions like wet - but rot it will, soon enough to embaras CO2 levels in the forthcoming critical period. Any plant fibre, if kept in rot-free conditions, like an unleaky building fabric/interior, remains 'permanently bonded' - until it isn't.

    I think you're being unduly critical, Tom. Firstly because hemp in hempcrete, or even straw in bales in walls, has a pretty low risk of being exposed to rotting conditions until somebody decides the building has reached end-of-life, and at that point being recyclable is an advantage. Secondly because hemp does store more carbon than timber - 'Hemp contains around 65-70% cellulose (wood contains around 40%, flax 65-75%, and cotton up to 90%)' according to https://ec.europa.eu/environment/forests/pdf/respondents-additional-inputs/European%2520Industrial%2520Hemp%2520Association%2520(EIHA).pdf

    Or are you suggesting there's no place for timber either in buildings?
  5.  
    Timber contains a higher proportion of lignin than soft plants do. Lignin contains a higher proportion of carbon than cellulose does (C6H6O2 vs C6H10O5). So it could be said that timber contains more carbon than soft plants do.

    However, such comparisons are meaningless without stating what you are using them for, you'd use a lot less timber than hemp to make your rafters, and the timber would be dried first.

    The government have an objective to increase the amount of timber used in buildings because it is a form of carbon storage, especially compared to using cement (or lime or hempcrete), though fire safety is an issue.

    But as Tom said, the storage is very short duration in climate terms.

    It would be better to use the site to grow trees, than to build a hemp-timber-straw house on it, if sufficient other (denser) housing sites were available.
    • CommentAuthorgyrogear
    • CommentTimeJul 13th 2020
     
    Posted By: WillInAberdeenyou'd use a lot less timber than hemp to make your rafters, and the timber would be dried first.


    a (surprisingly!) spurious argument, WiA, if I may say so !

    Nobody is talking about replacing timber with hemp *in construction* !!

    https://www.prima.co/magazine/the-history-of-hemp/

    gg
    •  
      CommentAuthordjh
    • CommentTimeJul 13th 2020
     
    Posted By: WillInAberdeenLignin contains a higher proportion of carbon than cellulose does (C6H6O2 vs C6H10O5).

    Lignin isn't a small specific molecule. It's a complex polymer and its makeup varies from species to species. I've seen figures that say the carbon content is anything between 40% and 60%. I haven't found anything definitive, I'm afraid. I do agree there is more of it in timber than in hemp.
  6.  
    Sounds like you're mixing up mol% with mass% then. Go back through your internet hits and count the ratio of C to O in each, in the form of their empirical formula of the format CxHyOz. Celluloses have almost equal carbons and oxygens (6:5), whereas lignins have many more carbons than oxygens. Both are classes of complex polymers.

    GG, that was exactly my point! that it is meaningless to claim "hemp stores more carbon than timber" when you don't use them in the same way.
    •  
      CommentAuthorfostertom
    • CommentTimeJul 13th 2020 edited
     
    Posted By: djhI think you're being unduly critical, Tom
    No, I think hemp's great - just wanting to expose that bit of commercial puff
    Posted By: gyrogearthe CO2 is permanently bonded within the fiber
    (not composed by gyrogear I hasten to add).
    •  
      CommentAuthordjh
    • CommentTimeJul 13th 2020
     
    Posted By: WillInAberdeenSounds like you're mixing up mol% with mass% then. Go back through your internet hits and count the ratio of C to O in each, in the form of their empirical formula of the format CxHyOz. Celluloses have almost equal carbons and oxygens (6:5), whereas lignins have many more carbons than oxygens. Both are classes of complex polymers.

    I don't believe I am making that mistake.

    The two are fundamentally different in nature.

    Cellulose is a long single chain polymer, created by sticking glucose molecules together by removing one water molecule per bond. It's the same everywhere and isn't particularly complex.

    Lignins are built from different basic building blocks in different types of trees, let alone straw and hemp. And they aren't single chains, they're complex branched structures, 'essentially phenolic in nature' according to Forest Products and Wood Science. The wikipedia article gives some idea of the complexity and variation, but not much in the way of hard numerical facts.

    But it's not really worth spending any more effort.
  7.  
    Indeed. Cellulose is made from glucose, polymerised by condensing H20 to leave (C6H10O5)n, which has 6 C to every 5 O. Different celluloses have different length chains with different crystal or amorphous structures and are made by different organisms. The monomers are added back-to-back in an alternating pattern.

    Lignin is made from addition polymerisation of three slight variations of a phenol ring (only one O) with a propenol tail (one more O), with varied methoxyl groups.The three monomers have C:O ratios of 9:2, 10:3 and 11:4, so they contain rather more carbon than cellulose does, and less oxygen and hydrogen.

    In summary: the claim that a cellulose-rich plant 'stores more carbon' than a lignin-rich tree, manages to be both wrong and meaningless!

    Incidentally, bugs like to eat glucose, but they hate to eat phenol. So cellulose-rich materials biodegrade and revert back into CO2 more readily than lignin-containing timbers do, they hang onto their carbon. That could be a good or bad thing depending on what you are trying to do with them.

    Edit: the previous links with strange claims about 'storing more carbon' and the like, all seem to originate from vendors of CBD potions. Would be nice to find out some objective info about hemp as a material, that didn't come from somebody flogging "Wellbeing essentials with functionally innovative botanicals". Anybody got any independent sources?

    Back to the original topic, forests do a whole lot besides storing carbon and delivering biofuel. Don't think any monoculture energy crops can replicate that.
    • CommentAuthorgyrogear
    • CommentTimeJul 13th 2020
     
    well, I still did not sign the petition - apparently the problem of CO2 fades into insignificance when one considers the amount of *methane* produced by trees !

    ''Methane is about 25 times stronger than carbon dioxide, with some estimates as high as 33 times stronger due to its effects when it is in the atmosphere''

    https://www.sciencedaily.com/releases/2017/03/170330190304.htm

    gg
    •  
      CommentAuthorfostertom
    • CommentTimeJul 14th 2020
     
    AFAIK, methane is just a 'concentrated' step on the way to good old CO2, because after production it soon breaks down into CO2 in the atmosphere.
    • CommentAuthorgyrogear
    • CommentTimeJul 14th 2020 edited
     
    https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

    I think it is a bit more complicated than that, Tom !

    Methane, as suggested in my previous link, is "far more dangerous" than C02 - it has a global warming potential that is 30-odd times more !

    (quotation marks becos they are *ALL* dangerous !) (LOL)

    "CH4 emitted today lasts about a decade on average, which is much less time than CO2. But CH4 also absorbs much more energy than CO2. The net effect of the shorter lifetime and higher energy absorption is reflected in the GWP. The CH4 GWP also accounts for some indirect effects, such as the fact that CH4 is a precursor to ozone, and ozone is itself a GHG".

    gg
    •  
      CommentAuthorfostertom
    • CommentTimeJul 14th 2020
     
    Posted By: gyrogearlasts about a decade on average, which is much less time than CO2
    You mean before the CO2 turns into a tree or sea shell? What does CH4 turn into then, in 'about a decade'? surely CO2 mainly?
    • CommentAuthorgyrogear
    • CommentTimeJul 14th 2020 edited
     
    Posted By: fostertomWhat does CH4 turn into then


    like you say, the methane is oxidized by the hydroxyl radical (*OH), into CO then CO2

    But (my point) before getting there, it does 34 times more damage than C02...
    And global methane production is expandng at a rapid rate for apparently unknown reasons...

    So my other point is, instead of leaving biomass lying around on the forest floor, burn it and do something useful with the heat - like allowing the local authority to heat gyms, schools & swimming pools with it...

    (Iran & China use it in road vehicles).

    OK, this produces C02, but that C02 would in any case get produced anyway !

    As an aside, that's why I won't sign the petition -- would anybody sign a petition to prohibit the nitrogen cycle, or the water cycle, or the lime cycle, or the carbon cycle etc. these are natural phenomena - IMO detractors need simply to ''get over it'' !!

    gg
    •  
      CommentAuthordjh
    • CommentTimeJul 14th 2020
     
    Posted By: gyrogearSo my other point is, instead of leaving biomass lying around on the forest floor, burn it and do something useful with the heat - like allowing the local authority to heat gyms, schools & swimmling pools with it... OK, this produces C02, but that C02 would in any case get produced anyway !

    Well two reasons ...

    (1) the biomass lying on the forest floor is essential to the ecology - leaving it is not accidental.
    (2) According to one of the references somebody posted earlier, coarse woody debris (CWD) can sometimes emit and sometimes absorb methane (edit: ah it was you! your science daily link) so isn't really a problem

    As an aside, that's why I won't sign the petition -- would anybody sign a petition to prohibit the nitrogen cycle, or the water cycle, or the lime cycle, or the carbon cycle etc. these are natural phenomena - IMO detractors need simply to ''get over it'' !!

    I don't understand this part. The petition is trying to ENCOURAGE the natural cycle by banning the unnatural act of burning it. So I don't follow your argument.
    • CommentAuthorgyrogear
    • CommentTimeJul 14th 2020
     
    ''banning the unnatural act of burning it''

    well, nothing unnatural in burning biomass, it's been done for centuries !
    (crop-stubble etc.)
    burning biomass is a well established technique in forestry management (Helps to prevent wildfires)

    gg
    •  
      CommentAuthorfostertom
    • CommentTimeJul 14th 2020 edited
     
    Posted By: gyrogearit does 34 times more damage than C02
    per what? per tonne? per mole? per daily output? Or is it that 34x as much of the total global heating is caused by methane, than is caused by CO2?
    • CommentAuthortony
    • CommentTimeJul 14th 2020 edited
     
    34 times as much as CO2 does by unit mass
  8.  
    GG, this might help: https://www.nature.com/articles/srep15991

    Much (most?) of the carbon stored in a forest is in the soil. This is constantly topped-up by dead plant matter falling on the floor and degrading down until it is fine enough to be incorporated into the soil. This is offset by some carbon in the soil being metabolisised and lost as CO2 or CH4, but the overall balance is in favour of carbon accumulating in the soil.

    In sites where trees were cut, it was observed that the floor lost carbon for many years subsequently (as you'd expect when the balance is disturbed and the supply of dead bits interrupted). It was worse where the small branches etc were also removed for fuel, as the whole soil lost carbon.

    In summary, worse emissions when trees and debris are removed, than when they stay in place.
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