How much CO2 does a tree absorb per year?

Translated by Laura Steeghs

Trees absorb carbon dioxide (CO2) from the atmosphere. The mechanism behind this is called photosynthesis. Trees use photosynthesis to turn CO2 into carbon and then store this carbon in their wood. During this process oxygen is released. Forests are therefore important CO2 reservoirs and planting trees is an efficient measure in combating climate change. But how much carbon does a tree store per year?

CO2 storage in trees in one year

How much CO2 does a tree store per year?

Across all tree species, a tree stores an average of 24.62 kg of CO2 per year.

This has been calculated by looking at the amount of CO2 that is stored annually by the following tree species: oak, beech, spruce, fir, Douglas fir, pine and larch.

Trees absorb carbon dioxide over their entire lifetime and store it as carbon in their trunk. An 80-year-old beech tree, for example, has stored 1,270.87 kg of CO2 in its lifetime. If we now divide this by 80 years, we can conclude that beech stores about 15.89 kg of CO2 annually.

If we do the same for the oak, beech, spruce, fir, Douglas fir, pine and larch trees, we find that these tree species store an average of 24.62 kg of CO2 per year.

How much carbon a tree stores depends on several factors. The type of tree and its age are the most important criteria.

How much CO2 does each tree species store in a year?

The CO2 storage per tree varies greatly. Broad-leafed trees store more CO2 than conifers when they are fully grown. However, conifers grow much faster than broad-leafed trees. Therefore, spruce trees are able to store more carbon in 80 years than beech trees.

The yearly carbon storage per tree:

Tree species CO2 storage per tree, per year
Oak 18,87 kg CO2/year
Beech 15,89 kg CO2/year
Spruce 20,13 kg CO2/year
Fir 20,72 kg CO2/year
Douglas fir 46,46 kg CO2/year
Pine 14,39 kg CO2/year
Larch 35,91 kg CO2/year

The data used for this calculation can be found in the Greenhouse gas inventory 2017, the most up-to-date data on carbon storage in trees.

Which tree stores the most CO2 per year?

The Douglas fir stores the most CO2. An 80-year-old Douglas fir stores about 3717.04 kg of CO2. Among the tree species discussed in this article, the Douglas fir therefore takes first place in terms of the amount of CO2 it stores.

douglas fir stores the most co2
A douglas fir absorbs annually 46,46 kg CO2

How much CO2 do trees absorb in their lifetime?

Strictly speaking, trees do not store CO2, they store carbon. During photosynthesis, trees absorb CO2 from the atmosphere. They convert this CO2 into oxygen and carbon. Then they use the carbon to grow and store it in their wood mass.

By measuring how much carbon is stored in the wood, we know how much CO2 a tree has absorbed. We look at a period of 80 years to compare the carbon uptake of different tree species.

An 80-year-old tree’s carbon absorption:

Tree species CO2 absorption per tree in 80 years
Oak 1509.59 kg CO2
Beech 1270.87 kg CO2
Spruce 1610.10 kg CO2
Fir 1657.24 kg CO2
Douglas fir 3717.04 kg CO2
Pine 1150.96 kg CO2
Larch 2872.63 kg CO2

The data used for this calculation can be found in the Greenhouse gas inventory 2017, the most up-to-date data on carbon storage in trees.

Why don’t we just plant conifers if they store more CO2?

Conifers sequester a lot of CO2. However, monocultural coniferous forests provide a much poorer habitat for animals and plants than near-natural mixed forests.

The function of mixed forests goes far beyond that of a CO2 reservoir. Though at first glance coniferous forests appear to be the better choice to compensate for CO2 emissions, mixed tree systems as a whole are able to absorb more CO2.

This has to do with the quality of the soil. In a mixed forest, soil quality is better than in a coniferous forest. When needles fall, they decompose less quickly. As a result, the soil becomes increasingly acidic. This leads to fewer microorganisms. Foliage, on the other hand, makes the forest soil alkaline. This increases soil activity and more CO2 can be stored in the forest soil.

Mixed forests also offer the added value of biological diversity. By planting mixed forests at ForTomorrow, we promote species conservation. Flora and fauna are better coordinated. Biodiversity increases.