permaculture

[dhondt <dhondt@eircom.net>]

On 28/07/16 05:51, Toby Hemenway wrote:
> 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.
I'm wondering whether this is obviously true Toby. Even when the growth 
rings get thinner does not necessarily mean that not tree does not make 
more timber.
This is basically a cylinder with ever expanding radius. A small 
expansion in radius may still mean that more timber is laid down than in 
a tree's youth when growth rings are fatter.
John
> 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.
>
> Cement: The minute you use even small amounts of cement, gone is all hope of 
> being carbon neutral; concrete is that big an energy hog. It takes hundreds 
> of millions of joules of energy to make a few pounds of cement. Almost 
> certainly the most energy intensive of any commonly used substance (cement is 
> #2 after water in tons transported per year).
>
> 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 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
>
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