Our Carbon Assumptions and Calculations
Our Carbon Calculations
Our carbon offset comes from two sources. Firstly, we have Emissions Avoided, a measure of the amount of carbon saved by not destroying existing forest. Secondly, we have Carbon Sequestration from the use of the Inga system as a regenerative farming system.
Interim Estimates From Evolving Research
For each hectare of Inga Alley cropping we estimate a minimum of a hectare of existing forest can be saved. This is based on comparison of maize harvest produced from Inga Alley areas compared to areas that have been subjected to Slash and Burn. While individual farmers use different cultivation patterns our best estimate is that this saving occurs an average of 3 times over a 20 year period, i.e. we take this as a reasonable average frequency for clearing new forest as Slash and Burned areas degrade. Burning primary forest produces 1617 tonnes of CO2 per hectare and burning secondary forest 808 tonnes, for an average of 1212 tonnes. Thus each Inga hectare saves at least 3636 tonnes.
We plant 2,500 Inga trees per hectare, so the saving per tree is roughly 1.45 tonnes.
Each Inga tree will additionally sequester a net average of half a tonne of carbon over 20 years by replacing unsustainable firewood, or by being buried as biochar, and as carbon sequestered into the soil via the trees’ roots or as mulch. By net, we mean the average after various deductions, for example what gets lost in the pyrolization process for biochar. Use of Inga pruning wood for cooking is a sustainable source of firewood that can replace the destructive use of forest trees which is currently practiced. Our average takes into account the different practices in South America and Cameroon.
Thus our total benefit per Inga tree is an average 1.95 tonnes of carbon saved over a 20 year period, or 97KG per year.
All these figures are estimates based on our initial research to date. We will update these figures periodically as new evidence becomes available.