Trees and Carbon

Graphic: Imperial College and Forest Research

Forests for Carbon or Where is the Carbon in a Forest?

Forest restoration is one of our best strategies for removing carbon dioxide from the air and slowing global heating. With woodland covering only 13% of the UK, we have no time to waste.

So which types of trees will capture more carbon?

The answer is complex. Up to 50% of a tree's dry mass is carbon and therefore a simplistic view would be that faster growing trees sequester more carbon because they grow faster. However, slower growing trees begin to catch up over time, and the oak can last for hundreds of years, locking carbon away for many lifetimes.

Is that the full picture?

No! In mature forests, 75% of the stored carbon is held in the soil, and the sequestration rates in the official Forest Research tables only give a nod to soil carbon.

We also need to consider biodiversity - all of the other inhabitants of a healthy forest, such as fungi, bacteria, protozoa, arthropods, earthworms and small mammals that all contribute to forest growth and the complex process of breaking down organic matter into humus and capturing carbon in the process. Birds and insects also help to pollinate trees and help the forest to grow faster.

The challenge ahead
The challenge facing humanity is long term carbon sequestration over many, many generations. Many governments are committed to significant forest restoration programmes, but most research to date has been driven by the commercial forestry industry, focusing on timber production, not on carbon sequestration.

For these new tree planting programmes to be effective tools in the climate emergency, we need to understand what is required to maximize carbon sequestration in new forests, in both the trees and the soil. How do we give these trees the best chance of survival? How do we help biodiversity thrive above and below the ground?

There is an urgent need to create new forests, to accelerate carbon removal and to support scientific research that can help these forests thrive for generations.

The Carbon Community will be launching our scientific field-trial in May 2021.
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