It’s a known fact that trees are only temporarily carbon sequesters and that by the time they start to rot, all the nasty material gets transmitted back into the atmosphere again. So why not prevent this? Thus far we’ve been held back from doing so because intervening into the natural cycle somehow doesn’t feel right. But if we only tidied up one sixth of all the tree wastage lying around on the forest floors, we’d be nearing the carbon levels emitted by burning fossil fuels.
That’s quite a compelling idea. Climatologist Ning Zeng who works at the University of Maryland, published a paper describing the impact of clearing up forests on a the Carbon Balance and Management Journal website recently. The article, now flagged ‚Äòhighly accessed’, was picked up by various other journals in no time.
It must be said that the numbers – Zeng made his calculations on the basis of national US forests and CO2 data- are enough to spark anyone’s interest. Zeng’s says that to relieve forests of some of their excess debris, could lead to a recurring carbon sequestering of 10 gigatons of carbon a year. Trees and plants are believed to scrub the air free of some 60 gigatons of carbon a year. Most of that gets emitted back into the atmosphere when living organisms decompose.
Removing one sixth of the debris before it sets out to rot away might be a hugely efficient way to prevent greenhouse gas emissions, says Zeng. So long as enough woody debris is left on the forest floors to feed new cycles and to maintain bio systems, this is a feasible solution. The dead wood is best stored air tight underground. That way a continuous carbon sink is created. Every square kilometer of forest would fill trenches of 10×25 meters in size and 10 meters deep. Some 10 million of those would have to be dug every year to store 5 billion tons of carbon at a cost of $14 per ton worth of buried wood.
The proposal will trigger odd associations because something natural is proposed to be treated as if it’s a chemical. And in some ways the proposed interaction (if not interference) with forests’ bio rhythms is risky to say the least. Nevertheless Zeng’s argument is no waste of time because the scientist has analyzed all the factors involved. Including the types of soil and their reactions to types of wood. And he admitted to New Scientist that in some cases, the creation of methene gases won’t be prevented. Methane is known as one of the worst greenhouse gas types. This indicates that extreme care should be taken before big mistakes are made. Also, burying a biomass like trees and plants will inevitably attract termites which would mess up the project by puncturing holes in the airtight burial chambers. That’s not to speak of the natural habitats of some animals that you might ruin by clearing out wood.
But on the other hand the advantage of Zeng’s proposal is that if it’s well executed, it’s highly efficient. To date there’s hardly any technology that could match up to a 100% efficient burial of biomass with such greenhouse gas reductions. You could also argue that it’s very likely that managed forests likely offer plenty of evidence that not all human interference in the natural cycle is bad.