How many trees contribute to the forestry carbon credits that I buy?
One cubic metre of timber is about 1.4 tonnes of timber. Each tonne of timber is about 50% carbon and 50% water, so there are 700 kilos of carbon per cubic metre of timber. Each pine tree gives about a cubic metre of timber when mature, and each cubic metre of timber has removed about 2.56 tonnes of CO2 from the atmosphere. Why 2.56 tonnes? CO2 as the chemical symbol indicates is two molecules of oxygen for each of carbon. When carbon is stored in a tree, essentially the oxygen molecules are separated from the carbon molecule in CO2. So each kilo of carbon has the equivalent of 3.66 kg of CO2. Simply multiply 700 x 3.66. Why 3.66, not 3? There are three molecules, after all. Because the weight of a molecule of carbon is only about 3/4 of the weight of a molecule of oxygen, and each time a kilo of carbon is sequestered by a tree, 2.66 kg of oxygen is released into the atmosphere.
