Bamboo and wood carbon

Bamboo is one of the best sources for making charcoal; it burns very well and has an exceptionally high calorific content, yielding more than 7000 kilocalories per kilogram. That’s equal to half the yield from an equivalent amount of petroleum.

Bamboo has several advantages over tree species in terms of sustainability and carbon fixing capacity. Available studies conclude that bamboo biomass and carbon production may be 7-30% higher compared to the fast growing wood species and producing 35% more oxygen than wood. For instance some tropical species measure at a total above ground biomass 287 t/ha with a mean annual production of around 47.8 t/ha/yr, almost twice that of the Eucalyptus clones. Interestingly, the total biomass of mature Bambusa at 6 years is in fact higher than that of teak at 40 years: 149 t C/ha versus only 126 t C/ha for teak. Besides higher biomass, bamboo has other advantages over wood as a carbon stock. Unlike woody crops bamboo offers the possibility of annual selective harvesting and removal of about 15-20% of the total stock without damaging the environment and stock productivity. Over 90% of bamboo carbon can be sequestered in durable products such as boards, panels, floors, furniture, buildings, cloth, paper and activated charcoal. These products have a very long life span and may retain carbon for several decades.

Actually, the practice of improving soil by adding charcoal is not some new revelation. This practice is used in different parts of the world and has even been traced back to the Amazon basin in the days before Christopher Columbus. People there created dark and productive soils (know as ” terra preta ” or “dark earth” soils) by adding charcoal mixed with manure. Those soils are still more productive today than surrounding soils that weren’t treated with charcoal.

In a study on the effectiveness of bamboo charcoal as a soil enhancer in the cultivation of tea and spinach, Hoshi Lab., (Tokai University, Japan) found, after three years, the bamboo charcoal tended to retain the supplied fertilizers in the rhizosphere. The bamboo charcoal also tended to keep the soil pH in a range that was suitable for the growth of tea trees. The heights and volumes of the tea trees in the plots in which the charcoal was used were, on average, 20% and 40% greater, respectively, than they were in the negative control. The plot that had the best tea tree growth had been treated with 100g crushed bamboo charcoal (particle size approximately 5 millimeters) per square meter per year.

While charcoal helps to clean the soil of pollutants, it also acts as a soil conditioner. It is used as a top dressing for gardens, bowling greens and lawns. Charcoal also acts as a substitute for lime in soil additives because of the potash content, and it can be a little cheaper than lime. It is used for potting and bedding compounds as a soil and mulch sweetener, and as a fertilizer and insecticide for roses. Some orchids seem to love it. One study showed that adding charcoal to the rooting medium of peas produced a marked increase in the weight of the pea plants and in nitrogen fixation by the plants as compared to controls. It is suggested that the benefits derived from charcoal are due to its adsorption of toxic metabolites that are often released by plant tissues, especially when the tissues are damaged. Charcoal is indispensable in rye grass seed production.