This from the Indy Letters page about the role of trees in the carbon cycle bears a thought:
How forests store greenhouse gas
Steve Connor's article "Forests losing the ability to absorb man-made carbon" (1 November) illustrates one of the most common misconceptions surrounding absorption of atmospheric carbon by trees: the misapprehension that forests are net absorbers of CO2.
A mature forest is incredibly useful to us as a store of carbon since any carbon that is fixed within the mass of a living tree is carbon that is not contributing to global warming. However, an existing forest can never help us in our plight unless it is spreading to cover more land. A mature forest (like a mature individual tree) is essentially "carbon neutral": it is absorbing only as much as it is releasing.
Unfortunately, there is not one significant area of mature forest on our planet that is increasing in size. We only get a net benefit when we plant new trees and thereby create new forest. We are in desperate need of more trees and the really sad thing is that this article will lead to fewer new trees being planted.
So... my banging on about not knocking down forests is valid, but not enough. Equally, I retain some significant doubts on many (not all) 'offset schemes' which, as I glibly put it, 'whack a fir in t' firmament - hey, an missed acronym: 'WAFIF'.
In fact, this kind of connects to my notion that using FSC-certified products might actually help over recycling by encouraging replanting. Or does it, as the net area does not expand... oh, my spinning head!
Indy - How timber can store carbon
2 comments:
No need to let your head spin too much, it is actually quite simple.
The letter writer is factually correct. Afforested areas are essentially carbon neutral as a living entity; they emit and capture CO2 pretty much in equilibrium. What they do do, however, is store an awful lot of carbon, which is released when the forest is cleared and burned.
FSC forests are sustainable in as much that all cut timber is always replaced by new tree plantings, thereby maintaining the status quo in terms of overall carbon levels.
He is also quite right in that the only way to use forests as enhanced carbon sinks is to actually create more of them. Unfortunately, as humans we are continually removing more and more natural forest and replacing it, in most cases, with other cash crops.
The palm oil post (below) is yet another twist on this. As the swampland forest is cleared, the land is drained and the underlying peat can no longer store its vast quantities of carbon. So in destroying this particular habitat, both the peat and the natural forest are destroyed, meaning man is pushing even more CO2 into the atmosphere.
The one thing that makes my head spin about this argument concerns what replaces the forest. I remember chatting to a biologist some years ago who told me that the effective carbon fixing leaf surface area of grassland that had been planted was often greater than that of the virgin forest previously there. (Don't know if you've ever been in a virgin tropical forest but pretty much the only thing that is green is the leaf canopy, below that it is dark and everything is largely dead and decaying.) However, most monocotyledons (grasses) are not as efficient at fixing carbon as trees etc are.
He also went on to explain that some fast growing crops (he mentioned hemp) are actually even more efficient at carbon capture than the original forest that they replaced, so perhaps there is an argument for deliberately replacing forests with certain crops in some circumstances? Now try and get your head around that one!
Nicely unspun, ta, which is what Junkk.com stands for!
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