Can US forestry mop up all US CO2 emissions?

Larry Caldwell larryc at teleport.com
Thu Dec 3 02:35:06 EST 1998


In article <7417jv$mt4$1 at nnrp1.dejanews.com>, dwheeler at teleport.com 
writes: 

> You are using as a model US forests which have been around for a while. But,
> as research done at OSU has shown, higher CO2 concentrations actually
> encourage trees to grow 2-3 times their normal rate, thus showing that trees
> _can_ remove considerably more CO2 than previously believed.

> Thus rapid-growing trees such as Red alder (Alnus rubra), hybrid cottonwoods,
> and the new hybrid willows can grow up to 13 feet per year for at least 15
> years. This produces trees which sequester CO2 _much_ more rapidly than
> before.

That is wonderful, but when the world production of fossil fuels releases 
more carbon than is contained in the active biosphere of the earth every 
decade, a few faster growing trees isn't going to do much.  The only way 
to stop the inexorable buildup of atmospheric CO2 is to quit burning 
fossil fuels.
 
> Also, remember that fossil coal deposits probably came from extensive
> forests, based on the numerous plant fossils found therein. I suspect, but
> cannot prove, that in years long gone, the earth had considerably higher CO2
> concentrations. This would make forest fires unable to function, since they
> must have at least 18-20% atmospheric oxygen to burn. Increased atmospheric
> CO2 would effective decrease the oxygen percentage, thus stimulating forests
> world-wide while increasing the world-wide temperature.

> What is know for a fact, is that during the Permian and Pennsylvanian huge
> quantities of coal beds were established, probably on any land then above
> sea- level. Such forests as established the coal beds could not exist in the
> presence of wide-spread forest fires.

Most coal beds are the remains of peat beds.  Sometimes the peat beds 
supported forests above them, sometimes not.  The important thing is the 
presence of an acid, wet anaerobic zone where plant matter can sink and 
be preserved.  I understand that even in the UK where peat beds were 
common, drainage projects have led to the rapid reduction of peat layers.

Volcanoes have been steadily ejecting carbon dioxide and methane for 
hundreds of millions of years, which is where many of our carbon and 
carbonate deposits got their raw materials.  It's doubtful that all that 
carbon was ever in the biosphere at once.

And in the carboniferous, the oxygen content of the earth's atmosphere 
was quite a bit higher than it is currently.  We know this because it 
supported huge insects that would choke to death in our own atmosphere.  
Insects breath through gas diffusion and spiracles, which is a very 
inefficient means of respiration.  A 20 cm dragon fly just could not 
exist today.

-- Larry



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