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New Dryland Forests Can Be Major Carbon Sinks! |
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Ah, this is nice. And I cannot help but feel that people are beginning to listen to what I've been saying in these pages ever since 1985. Here is the recognition that the vast dryland regions of the Earth present a ready opportunity to double the Earth's forest cover, and so end the Greenhouse Effect. |
Two major points are mentioned in this abstract of the following abstract of the original article.
The first and most important point is that forests are - as long as they exist - 'permanent' carbon sinks. This is currently not widely known and understood in the sciences. The second, and equally important point, is that forest are not - I repeat, are not - "balanced" carbon sinks (releasing as much CO2 via decay as they absorb, as widely believed and taught), but 'growing' carbon sinks. The constant increase in their mass alone results in increased carbon sequestering, and the natural increase in area covered - if left to expand - results in another increase in carbon sequestering.
In addition, such new forests in drylands will also store and husband water, as well as temper the local climate - all as stated in these pages long ago, but still not generally known and understood in the sciences. It is nice to see though that the authors mention that such forests also present a valuable resource to local populations - also as long stated in these pages.
Also mentioned in this article is the fact that there is a decrease in photosynthesis - and a consequent ~10ppm increase of atmospheric CO2 - during the winter when the large deciduous component of Northern hemisphere forests is dormant. Altogether, I cannot help but be much pleased that my assertions have been found to be right on the mark.
Finally, and I cannot help but mention this wonderful apt coincidence, the author's name "Gruenzweig" is a German word which, when translated into English means, "Greenbranch". |
Original Abstract
AN OFF SEASON CARBON SINK
In most plant species, the efficiency of water use during photosynthesis is increased by higher CO2 concentrations. Therefore, elevated atmospheric CO2 concentrations (from the burning of fossil fuels) would permit afforestation in drier regions. Drylands occupy vast areas of the globe, and greater forest cover would presumably increase carbon sequestration as well as provide a natural resource for local populations. In order to determine whether such an opportunity might exist, Grünzweig et al. conducted eddy flux, physiological, and inventory measurements in a 35-year-old forest (2800 hectares) at the edge of the Negev desert and evaluated the carbon balance of this system. The dryland forest stores 6.5 kg of C m-2 and accumulates 0.13 to 0.24 of kg C m-2 yearly. The uptake of CO2 is highest during the winter, which is out of phase with most Northern Hemisphere forest activity and would expose low-latitude forests to CO2 concentrations ~10 ppm higher than those in the summer. Expanding such afforestation efforts into regions of sparse shrubs and C4 grasses could lead to significant carbon sequestration.
[Global Change Biol. 9, 791 (2003) -- HJS, Science, May 24 2003 - in Highlights of recent literature]
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