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<DIV>Hi Ron, It's been a while, </DIV>
<DIV> So we both agree there seems to be some
conservative estimates of POTENTIAL Biomass production even when we are watching
and recording it happen. Well, yes. </DIV>
<DIV> Did we measure the 6 years of leaves left to
compost on the ground, or the increase in root volume in the stump? </DIV>
<DIV> Just burning only the small stumps and stray roots,
following clearing my farm lot will add maybe up to 5% of my biomass harvest.
Since I am burning most of the smaller brush off having friendly bonefire
gatherings, there is no need to cut the bigger stumps up and get dirt on the
chainsaw blade. They keep the brush fire going. I am amazed how hard the scrub
dogwood char is. </DIV>
<DIV> I have a 300 gallon oil tank on its side, on a
skid, with the top 2/3 cut open to manage brush burning, Maybe something
interesting will evolve from this. I use it to contain ash. I can move it around
the lot where ever I need to bring it near the pile being managed. Right now I
collect ash for the lawn and garden. In the future I may collect char as well.
Maybe I can make a lid that reduces the air intake and use the lid as soon as
the brush burns down into the container. Right now I put whole saplings in there
and burn them from the brush end in.The stem and even the stump hang out the
side. </DIV>
<DIV> I also have been planning on using larger
stumps as reinforcement on the banks of manmade Bobcat creek. In managing forest
ar farm lands I cannot make a strong enough point about erosion control. Dirty
stumps, can be dumped into washouts. then just add some dirty soil with the
toughest weeds you can find in it. By the time it settles, it is as good as rock
in fence wire boxes. On my lot I will use the Hedge Apple stumps for this as
they are slower to rot. </DIV>
<DIV> If you do have to cut up stumps, let them sit in
the rain and rotate them till all the dirt washes off. Then use a chain or blade
you don't mind to sharpen soon.on your saw ;-) </DIV>
<DIV> </DIV>
<DIV> Dan Dimiduk </DIV>
<DIV> . </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>In a message dated 11/15/2013 1:21:40 PM Eastern Standard Time,
rongretlarson@comcast.net writes:</DIV>
<BLOCKQUOTE
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<DIV>Dan and list:</DIV>
<DIV><BR></DIV>
<DIV> 1. This is partly picking up on your ”Is this correct”
question below. The answer is yes.</DIV>
<DIV><I><BR></I></DIV>
<DIV><I> </I>2. I think you were making your calculations from p
23 of the recommended report, which said:</DIV>
<DIV><BR></DIV>
<DIV>
<DIV><I>A six-year cycle was recommended to ensure maturity.
Harvesting </I></DIV>
<DIV><I>started in 2008 and it emerged that 6-year old acacia trees produce
heavier charcoal than 4-year old </I></DIV>
<DIV><I>acacia trees. Under ideal conditions and efficient conversion, it has
been estimated that an acre of land </I></DIV>
<DIV><I>should produce about 300 bags (40 kg) of
charcoal. </I></DIV></DIV>
<DIV><BR></DIV>
<DIV> Using metric, your 7.3 tons biomass/acre converts to about
7.3*(2/2.2)*2.47 = 16.4 tonnes biomass/ha-yr = 1.64 kg
biomass/sqm-yr = 0.8 kg C/sqm-yr (assuming biomass is about half carbon)
And these are bone dry tones. Can maybe double for wet
tonnes.</DIV>
<DIV><BR></DIV>
<DIV> Or, sticking with metric, the harvest is 300 * 40 = 12,000 kg = 12
tonnes char per acre per harvest, or 2 tonnes char /acre-yr. Same as
about 5 tonnes char/ha-yr or 4 tonnes C/ha-yr (assuming char is 80%
carbon). Using your conversion efficiency of 0.3 (w char to w biomass),
this is about 5/.3 = 16.7 tonnes biomass/ha-yr - which is essentially
the same that you obtained in English units. But also 30% is
awfully good in any kiln. If they were only to get 25% conversion, they
would have needed to start with an NPP of 5/.25 = 20 tonnes biomass/ha-yr or
about 10 tonnes C/ha-yr = 1 kg C/sqm-yr</DIV>
<DIV><BR></DIV>
<DIV> One reason for going through this is to compare to global
NPP averages which is about 60 Gt C/yr divided by about 12 Gha = 5 tC/ha-yr.
Kenya being twice as large as the global average sounds OK. I’ll
bet they can do appreciably better in those parts of Kenya with enough
rainfall.</DIV>
<DIV><BR></DIV>
<DIV> 3. My main reason, however, for following up is
to note that this 2010 study by Practical Action nowhere talks about
char-making stoves. It also is full of talk about the illegality of most
char making. In the above example, there is mention only of a six year
cycle - no pollarding (like coppicing) apparently - chopping down the whole
tree every six years? I think they can do a lot more cooking (have
faster regrowth of the forests) than with the assumption of producing char
with no use of the pyrolysis gases (which are presumably not even flared).
So I hope for another study by Practical Action which includes the
option of switching from jikos to char-making stoves. That is - moving
wood - not char. It was disheartening to read about the illegal taxes
that hurt the producers. I wonder if there is also illegal taxing of
wood?</DIV>
<DIV><BR></DIV>
<DIV> 4. Not really pertinent here, but when I lived in
Sudan, the chief forester for the country confessed he was (illegally -
prohibitions against introducing exotics) throwing out mesquite seeds at every
opportunity. The seeds of the acacia don’t make it through the local
animals (goats, etc), but mesquite seeds do. He was pleased with his
success.</DIV>
<DIV><BR></DIV>
<DIV>Ron</DIV><BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
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