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oanalysis that makes us This is a multi-part message in MIME format. ------=_NextPart_000_305C_01D14B05.5B802720 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 No virus found in this message. Checked by AVG - www.avg.com Version: 2016.0.7294 / Virus Database: 4489/11362 - Release Date: = 01/09/16 ------=_NextPart_000_305C_01D14B05.5B802720 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML xmlns=3D"http://www.w3.org/1999/xhtml"><HEAD> <META content=3D"text/html; charset=3DUTF-8" http-equiv=3DContent-Type> <META name=3DGENERATOR content=3D"MSHTML 8.00.6001.23588"> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <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