Together as business leaders, we can make a difference.

'Heroes of Net Zero' Follow Us

Why do mature Trees Have No C02 Value?


Chris Rea explores the curious balance sheet applied to carbon credits and official measures designed to combat deforestation.

One of the most effective ways of removing carbon from the atmosphere is preserving and expanding our forests. However, existing schemes aimed at encouraging this appear to ignore the importance of the mature trees that do the heavy lifting in combatting climate change.

To encourage planting of trees, carbon credits are now actively counted and traded and are increasingly becoming of interest to businesses as vehicles for offsetting their carbon footprints.

However, the GHG Protocol Committee guidance from 2023 says that an organisation can only claim the amount of carbon from a newly planted tree, which the tree actually removes in that year.

This means carbon credits assigned to newly-planted trees are negligible, while pre-existing mature trees that after several decades can absorb around 170 kg of CO2 per year, are not counted at all.

That’s right. Under what is known as the principle of additionality, if the woodland already exists no carbon credits can be claimed. Of course, this also means that when you cut woodland down, there is no carbon credit loss on the balance sheet.

It is scientifically correct that saplings, once planted, can take decades to become effective carbon sinks, but where is the science which says that the trees that exist have got no CO2e value? If they have “no value” they are less likely to be cared for and preserved and there will be a continuing incentive to cut them down for their timber or for more profitable land use. 

Meanwhile, AESSEAL plc has planted hundreds of trees to create Tree Walk, a one kilometre long perimeter attraction mainly intended to attract schoolchildren and encourage them to take up STEM subjects. The business will also plant hundreds more semi-mature trees, the largest we can buy that can be transplanted, as we landscape The Factory of the Future.

We wanted to go a lot further, but after a huge time and cost investment, working with BSI in order to explore environmental investments that could offset our own carbon footprint, the GHG Protocol’s updated guidance means that AESSEAL has abandoned plans to buy marginal farmland and grow trees, as it would take 30 years for those trees to absorb a significant amount of CO2e. 

Instead we have decided to buy an existing forest or forests, which are a thing a beauty in themselves. AESSEAL plc has already spent £7.7 million on displacing green energy with self-generated renewable energy, which gives us no emissions reductions benefit on our CO2e scorecard, so we are not that driven to make environmental decisions that purely impact on our Scope 1, 2 and 3 emissions calculations.

Hopefully, common sense will eventually kick in and the world will seek to conserve the trees and forests that we have, a part of which will be by assigning the appropriate scientific CO2e absorption value to existing mature trees.

Follow the journey and keep up to speed with the updates in our Betterworld.Solutions magazine and the #29millionby29 campaign on Chris Rea’s LinkedIn.


If enough businesses act, together we can slow down or help to prevent Global Warming.

A Summary of Evidence

We estimate that widespread adoption of more climate-friendly policies in industry globally, could have the equivalent impact of taking 630.5 million cars off the roads.

Real World Examples

Just a few examples where we have the know-how to do things differently and help both the environment and the bottom line.

Create your Policy

The case for a great return on investment, from water and energy savings is very clear. "Adopt an Investment Policy to Prevent Global Warming".