The role of carbon sequestration

A growing issue

As more companies seek to reduce their carbon footprint, we’re seeing enquiries about carbon off-setting increase. While ITF plants trees primarily for local community and landscape improvement, we recognise that many people are interested in knowing how much carbon dioxide is sequestered by the trees we plant. The problem is that the method for calculating how much carbon is sequestered is far from straight forward. This applies to carbon credit based schemes and those projects such as ours, for which carbon sequestration is an outcome of tree planting rather than an objective.

In this blog, you can see how we calculate CO2 sequestration, the methodological limitations, and the benefit of focusing on the community rather than trees alone. Remember, it’s all about the right trees, in the right place, and for the right reasons.

Working with limited data to generate a model

We’ve been grappling with the role of carbon off-setting in our own work for some time, not least because the fundamental need is to reduce fossil fuel use rather then ‘off-set’. Moreover, the available research and data for calculating CO2 sequestration in trees is uncertain. So many factors influence sequestration, including species, climate, altitude, soil, the local ecology and so on, and how all these factors interact is no-where near fully understood. That said, tree and forests do convert CO2 into carbon in biomass.

Our approach to building a model is therefore conservative and limited to specific regions and planting configurations. To calculate CO2 sequestration, we use values and formulas provided by the IPCC’s Guidelines for National Greenhouse Gas Inventories (Vol. 4)[1]. Our model is only valid for forest restoration projects in African Montane Tropical Systems, such as many of our sites in Kenya and Uganda. We assume 1,000 trees per hectare, 85% survival rate, and limit the annual sequestration rate to a 20y growing period.

How much CO2 per tree?

Using our model, our business partners can state that each tree planted sequesters 14.7kg of CO2 each year for 20 years. A company which supports the planting of 100,000 trees each year would therefore reduce their annual carbon footprint by 1,470 tonnes. That’s 29,400 tonnes over 20 years – a significant contribution for a company.

Tree planting for the right reason

The trees, however, need to survive. So the right trees need to be planted in the right place and for the right reasons. And the communities whose livelihoods and wellbeing depend wholly or partly upon the health of local forests, are the people whose reasons for forest restoration need to be heard.

Local communities need to be involved in tree planting projects from the outset. These are the people who will, if involved properly, become the forest’s stewards. They will ensure the trees’ vital role in increasing biodiversity and ecosystem services such as water, fuel, food and carbon capture, will last for generations.

 

By James Kemp, ITF Head of Fundraising and Communications

 

[1] https://www.ipcc.ch/report/2019-refinement-to-the-2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/