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Hi Paul & All, Jan 9, 2016
Yes Paul it does but the atmospheric average does not bear =
faithfully on CO2 near the ground where plants grow.
I have not looked at this in many years so dates are approximate and =
details may be a bit scrambled. In about 1925 someone tested the idea =
that increasing CO2 in a greenhouse would increase growth rates. =
Contrary to expectation it decreased rates.=20
Much later it was discovered that the apparatus used to generate CO2 =
was also generating a byproduct (ethylene I think) which decreased =
growth. When this was removed the growth rate increased as expected. =
I think somewhat elevated concentrations of CO2 are (or were) used =
commercially for the purpose of increasing growth. If it is raised too =
high things get out of wack.
In the early 50s I read a copy of Geiger; The Climate Near the =
Ground. published 1913 ? He had assembled a huge amount of information =
on gradients of CO2 near the soil surface and at modest heights above =
it; all in calm air conditions. At night this is partly due to nearby =
plants (CO2 is heaver than air I think) but mostly it is due to soil + =
root respiration. Low plants like Violets probably benefit from this.=20
Recently, probably 80s, CO2 and temperature up to 12 Metres above =
field crops was recorded at various heights to enable modeling of =
photosynthesis.=20
=20
Another entirely different case shows how interpretation of =
observations can be tricky. Someone noticed that a small zooplankton, =
raised in a room that was isolated from daylight, started to go into a =
reproductive phase at the same time each year. Clearly it had some =
built-in biological calendar and turned on the juice when the right day =
arrived.=20
Quite a few years later this was found to be due to some chemical =
that was produced each year (perhaps by the same zooplankton) at the =
same time in the local reservoir and not removed during treatment. =
Details may be scrambled a bit but this is the basic story.=20
Yt, Dave Webster
=20
----- Original Message -----=20
From: rita.paul@ns.sympatico.ca=20
To: naturens@chebucto.ns.ca=20
Sent: Saturday, January 09, 2016 11:35 AM
Subject: Re: Fwd: [NatureNS] Red Herring & Forestry
=EF=BB=BF I couldn't agree more Dave!=20
One thing I always wondered about was CO2 and food production.=20
Seems its essential for to grow food - does increasing the CO2 level=20
increase the yield of crops? the growth rate of trees?=20
Enjoy the winter=20
Paul=20
=20
On January 9, 2016 at 10:00 AM David & Alison Webster =
<dwebster@glinx.com> wrote:=20
=20
----- Original Message -----=20
From: Nicholas Hill=20
To: naturens@chebucto.ns.ca=20
Sent: Friday, January 08, 2016 12:01 PM=20
Subject: Re: Fwd: [NatureNS] Red Herring & Forestry=20
=20
"when we cut the forest and ploughed our prairies, we never knew =
what we were doing because we never knew what we were undoing" (Wes =
Jackson citing a Wendell Berry letter)=20
<snip>=20
Hi Nick & All Jan 9, 2016=20
With reference to the above quote, I assume you will agree =
that those who preach should be prepared to live within the confines of =
their sermon.=20
=20
In this case, in justice to those pioneers who risked all and =
endured hardship for a shot at a modest slice of "Freedom from Want and =
Fear" would it not be appropriate, for those who spread or accept this =
view, to dispense with clothing, live under a rock and eat sow bug =
dropping ?=20
=20
Surely you will also agree that it is unseemly to denigrate =
those long dead and especially unseemly to feast at the banquet which =
they made possible while doing so.=20
=20
Yt, Dave Webster, Kentville=20
=20
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<DIV>Hi Paul & All, =
=20
Jan 9, 2016</DIV>
<DIV> Yes Paul it does but the atmospheric average =
does not=20
bear faithfully on CO2 near the ground where plants grow.</DIV>
<DIV> I have not looked at this in many years so dates =
are=20
approximate and details may be a bit scrambled. In about 1925 someone =
tested the=20
idea that increasing CO2 in a greenhouse would increase growth rates. =
Contrary=20
to expectation it decreased rates. </DIV>
<DIV> Much later it was discovered that =
the apparatus=20
used to generate CO2 was also generating a byproduct (ethylene I think) =
which=20
decreased growth. When this was removed the growth rate increased as =
expected.=20
I think somewhat elevated concentrations of =
CO2 are=20
(or were) used commercially for the purpose of increasing growth. If it =
is=20
raised too high things get out of wack.</DIV>
<DIV> &nbs