BY DR. JOSE PALU-AY DACUDAO
IN THIS article, we identify processes and things massively made by humans that act (or not act) as carbon sinks, taking into account the basic principle above.
What about forestry products such as wooden houses, buildings, and other infrastructures. As long as they do not burn down and are protected from decay, they do act as carbon sinks.
An example in the Philippines is falcata forestry plantations. Falcata is a fast-growing tree of the nitrogen-fixing legume family (Fabaceae). Since it is a nitrogen fixer, it doesn’t need any nitrogenous fertilizer and grows very fast as long as it has access to plenty of water.
In brief, falcata trees are ravenous carbon dioxide gulpers, transforming it massively into lignin. After seven to 10 years, these lignin-rich trees in a plantation are harvested and turned into plywood and other woody stuff that makes up houses and woody infrastructures.
As long as these woody infrastructures are not burned down or biologically decay, they represent a carbon sink. (As noted previously, lignin is very difficult to biodegrade.) Therefore, falcata forestry is a process that sequesters carbon away from the air, lessening atmospheric carbon dioxide.
How about the traditional practice of burning the remains of sugar cane (or other woody material) after a harvest, and then plowing the resulting char into the soil? Yes, it is a process that sequesters carbon away from the air, lessening atmospheric carbon dioxide.
Traditionally, it is known NOT burning will result in crop failure. (Never mind the Philippine’s clean-air act, which needs to be amended, or just abolished and cleaned out, leaving anti-pollution laws to local government units that know the local conditions better.) It happens that burning the harvested field results in charring of the woodier parts of the mature sugar cane. This produces charcoal.
In case of the sugar cane fields of Negros, ever wondered why some of them have been growing cane for more than a hundred years, and yet remain well-conditioned?
Once plowed into the ground, char (carbon) results in a carbon-rich soil, the same as the very fertile and famous tera preta of the Amazon. Soil rich in elemental carbon retains water, minerals, and other nutrients far better than soils that are not, and prevents acidification.
It has turned out that the slash and burn system, which by legend is detrimental to the ecosystem, that native Amazonians have employed has actually resulted in one of the richest soil in the world, wherein plants grow faster and denser.
Moreover, according to the formula describing charring, which is also a form of carbonization [C6H12O6 (organic compound) → 6C + 6H2O], the carbon organic material becomes fixed as elemental carbon for a very long time. Recall above that elemental carbon is quite difficult to oxidize and does not biologically decompose. Once buried in the soil, it tends to stay there permanently. (To be continued)/PN
