How much carbon does a tropical tree sequester? (Part 2)

Continuing from Part 1 (previous Post), let me cite some additional studies and methodologies. A Dutch study entitled “Estimation of Tropical Forest Biomass for assessment of Carbon Sequestration using regression models in remote sensing in Berau, East Kalimantan, Indonesia” by Irvin K. Samalca, Alfred de Gier and Yousif Ali Hussin, of the Department of Natural Resources at The International Institute for Geoinformation Science and Earth Observation confirms and shows that 50% plus of a tropical tree’s woody biomass is carbon. That means that fast growing tropical trees like those planted by CO2 Tropical Trees and Amazonia Reforestation, which reach maturity in just 10 years, are excellent carbon storage vessels.

Let’s calculate this from a different perspective. We know from several studies  that the woody biomass of a tropical tree plantation can increase by at least 35 cubic meters plus (14,382 board feet) per hectare per year. Depending on the hardwood species, one cubic meter (424 board feet) of tropical hard wood can weigh from 600 kg to 1,200 kg (1,322 lbs to 2,645 lbs). Assuming 1 hectare of trees with a gain of 35 cubic meters of wood times a conservative average of 750 kg (1,653 lbs) per cubic meter, and you get 26,250 kg (57,871 lbs) per hectare per year. If at least half of that woody biomass is carbon, then one gets 13,125 kg (28,935 lbs) of carbon. Divide 13,125 kg of carbon by an average of 600 mature plantation trees (after culls) and one gets 22.6 kg (50 lbs) per tree, the number used by CO2 Tropical Trees.

Why conservative? There is ample scientific support for much higher carbon sequestration rates by tropical trees. For example, Reforest the Tropics is an applied research program in Costa Rica demonstrating climate change mitigation through sustainable farm forestry. Using a 40 year base line they suggest that a natural tropical forest can sequester between 100 US tons to 160 US tons of carbon per acre (90.7 metric tons to 145 metric tons). This translates into 224 metric tons to 356 metric tons per hectare stored in a natural tropical forest over 40 years. Their research also suggests that a managed plantation of tropical trees will store as much as 800 US tons of CO2 per acre (725 metric tons). That translates into 1,792 metric tons per hectare. If one were to take 1,792,000 kg and divide by 40 years and then divide again by 1,250 tropical trees planted per hectare one would get 35.85 kg (79 lbs) per tree per year.

CO2 Tropical Trees is actually relying on the most conservative estimates of carbon sequestration for its carbon neutral program. They are not alone in relying on those numbers. For example, Carbonify has a carbon calculator that is based on 22.6 kg or 50 lbs of carbon per tropical tree per year. Another example is the article by James Post, citing a 2005 study in Wikipedia that uses 22.6 kg or 50 lbs of carbon sequestration per tropical tree per year for the purpose of calculating carbon offsets. In conclusion all I can say is that every time someone funds the planting of a tropical tree with CO2 Tropical Trees or with Amazonia Reforestation, the very least they can expect from that tree is 22.6 kg or 50 lbs of carbon sequestered per year from our atmosphere. Given these facts and numbers people and institutions really don’t have any more excuses for not funding tree planting as an obvious partial solution to climate change.

Carbon Offsets and Tropical Trees

The issue of carbon offsets is very important in Europe, and slowly gaining ground in North America. In May of 2010 the public market for carbon offsets was around €16 Euros ($20 USD) per metric ton (2,204 lbs). I am going to show in this article why planting tropical trees is a much more cost effective method of carbon sequestration for a company or business seeking to offset its emissions, than is the purchase of carbon offsets in the public market. For that purpose I am going to use a hypothetical ABC Company that needs to purchase 10,000 metric tons (10,000,000 KG or 22,046,226 lbs) of carbon offsets every year to balance its emissions.

The average fast growing tropical tree, like Acacia mangium or Eucalyptus pellita, sequesters 22.6 KG or 50 lbs of carbon per year. That means that one would have to plant 442,478 tropical trees to balance 10,000 metric tons of emissions every year. In order to account for any losses of trees planted to disease, pests, drought or fire, I am going to round up that number to 500,000 tropical trees, providing an ample safety margin for ABC Company’s carbon offset requirements. The cost of planting and maintaining each tropical tree for carbon sequestration purposes for a period of 10 years is approximately €1 Euro per tree ($1.27 USD in May 2010). That means that ABC Company would have to spend €500,000 Euros or $635,000 USD to plant sufficient tropical trees to offset 10,000 metric tons of emissions for a 10 year period.

The reason for the 10 years is simply that the average tropical tree is most effective at carbon sequestration in the first 10 years of its life, after which its effectiveness declines. That is why organizations like CO2 Tropical Trees work and calculate how they balance emissions on the basis of a 10 year cycle. ABC Company may have one other additional expense of approximately $30,000 USD or €23,630 Euros to obtain carbon certification of the trees planted, should it require the same for legal, political or tax reasons. Needless to say, planting tropical trees in the Orinoco or Amazon basins of South America provides ABC Company with excellent public relations and advertising value as well, given ther increased consumer demand for “green” business conduct.

Now let’s compare these numbers to the cost of purchasing carbon offsets from the public markets. At €16 Euros per metric ton, ABC Company would have to spend €160,000 Euros every year for 10 years to offset its carbon emissions, or a total of €1,600,000 Euros ($2,032,000 USD). That is an amount that is more than 3 times higher than the cost of planting tropical trees to offset its emissions. This means that funding the planting of tropical trees is not only more cost effective than purchasing carbon offsets in the public markets, it is also better for the environment, as trees seed clouds, expand wildlife habitat, and have a significant impact on socio-economic conditions in developing countries like Colombia, Venezuela or Brazil. Tropical trees also remove a number of pollutants other than carbon from the atmosphere, and depending on the species used can greatly enhance soil fertility for permaculture activities. Organizations like CO2 Tropical Trees and Amazonia Reforestation, when planting for carbon sequestration purposes, also plant native tree species, whose conservation enhances global biodiversity.

Dexter B. Dombro, B.A., LL.B., is a former lawyer who is actively engaged in afforestation and reforestation projects in the Orinoco river basin of Colombia in South America. His web sites include http://www.co2tropicaltrees.com/ for carbon sequestration and http://www.myreforestation.com/, while his blog on investing in tropical trees can be found at http://co2tropicaltrees.blogspot.com/.  The plantations Dexter works with are also associated with the University of Alberta in Edmonton, Canada, and the Swiss-based NGO Weforest.

There are 3 principle ways of offsetting carbon. The first, and my favorite, is to be pro-active and to do something that will actively sequester CO2 from the atmosphere. Planting tropical trees qualifies in spades, because as each tree grows it absorbs carbon at an average rate of about 50 lbs or 22.6 kg a year. The second way, and my least favorite, is what I call the status quo or do nothing approach. This is where you agree to not chop down the forest or to not fly someplace. In other words, if one doesn't do something then no CO2 will be generated. The third approach, almost as important as the first one, is to actively reduce the CO2 one is producing, so for instance insulating one's house, turning the thermostat down, changing to energy efficient light bulbs, installing and using alternative energy sources like solar, wind or hydro power. Well, I'm sure you get the idea.

I actively promote CO2 Tropical Trees, which is a program dedicated to helping consumers like yourself make your car carbon neutral. The program relies on the US Environmental Protection Agency's finding that the average North American car emits 12,100 lbs of CO2 every year. That means that it takes an average of 242 tropical trees, each absorbing 50 lbs of CO2 a year, to offset the emissions of your car. The CO2 Tropical Trees program plants 250 tropical trees and cares and maintains them for you for a 10 year period, meaning that your car can be carbon neutral for those same 10 years. The cost of doing this is only $750 for all 10 years, or by annual subscription of $85 a year. To make it simple, you could offset your car's annual CO2 emissions for the price of just a single fill-up at the pumps, or about $0.20 a day.

Besides knowing that you did the right thing, your funding of the tropical trees they plant gets you an annual bumper sticker and windshield decal that lets you brag to your neighbours, friends and associates about the fact that you are doing something "real" in the fight against global warming and climate change. Equally important, the tropical trees being planted provide invaluable habitat and food for endangered wildlife. Part of the CO2 Tropical Trees program is dedicated to setting up a Natural Reserve on plantation land in cooperation with the world renowned Omacha Foundation. Simply put, this is a socially responsible and "green" activity you need to do right away.