Does planting trees remove CO₂?

Yes, while the tree grows and for as long as it stands. How much depends on the species, the place and the years. Here is how a tree's carbon is counted, what makes tree planting work for the climate, and what a tree-planting carbon credit should prove.

The short answer

A tree takes CO₂ from the air through its leaves, keeps the carbon and releases oxygen. The carbon ends up in its trunk, branches and roots, and part of it in the soil around them. About half of the dry weight of wood is carbon (IPCC Guidelines, Volume 4).

So a growing tree removes CO₂. But the carbon only counts for the climate if three things hold: the tree survives, the carbon stays put for decades, and the tree would not have grown there anyway.

THE METHOD

How much CO₂ does a tree absorb?

There is no single number. A sapling adds only a little carbon each year, a vigorous tree in its prime adds far more, and an old tree grows slowly again. Species, soil, water and climate change the result many times over. That is why a figure "per tree" means little without the method behind it. This is how foresters and carbon standards count:

1. Measure the tree. The diameter of the trunk at 1.3 m height, and often the height of the tree.

2. Estimate its dry weight. A published formula for that species, an allometric equation, turns diameter and height into the dry weight of the trunk, branches and leaves. The roots are added with a root-to-shoot factor.

3. Take the carbon share. Multiply by the carbon fraction of dry wood. The IPCC default is 0.47.

4. Convert carbon to CO₂. Multiply by 44/12, about 3.67, because a molecule of CO₂ weighs that much more than the carbon atom in it.

5. Count the change. Do the same a few years later. The difference is what the tree took up. A project then subtracts what the land would have held without it.

A worked example. Say the formula puts a tree, roots included, at 1,000 kg of dry wood. That holds about 470 kg of carbon (1,000 × 0.47), which is about 1,720 kg of CO₂ (470 × 3.67) taken out of the air over the tree's life so far.

What makes tree planting work for the climate

The right place. Trees belong where forest is the natural cover. Planted on peat, wet grassland or species-rich meadow, they can release soil carbon that takes decades to win back, or more than they ever store (Friggens et al., 2020), and cost biodiversity.

The right trees. Mixed, native forest that is allowed to grow old holds far more carbon over time than a plantation that is harvested every few decades (Lewis et al., Nature, 2019). Where seed trees are near, letting forest return by itself can cost less than planting and brings back local biodiversity better (Cook-Patton et al., Nature, 2020).

Survival and care. A planted seedling is a promise, not a removal. What counts is the tree that is still growing after ten, twenty, fifty years.

Permanence. Fire, drought, pests and felling put the carbon back in the air. A credible project monitors for years and holds a reserve for losses.

Time. Most of the carbon is taken up in the decades after planting. Trees planted now help most in the second half of this century.

Planting trees cannot replace cutting emissions. It is part of the second half of the climate solution: taking carbon back.

CREDITS

Tree planting carbon credits

A carbon credit, or certificate, stands for one tonne of CO₂ removed from the air. For trees, a good one should prove:

It was measured, not only modelled. Some credits are sold up front, on what the trees are expected to absorb in the future. Others are issued after the carbon has been measured. Ask which one you are buying.

It is additional. The trees would not have been planted or kept without the project.

It is protected against loss. There is monitoring, a buffer for fire or felling, and someone responsible if the carbon is lost.

It is counted once. It sits on a public registry, so the same tonne cannot be sold twice.

Europe's new CRCF regulation asks the same questions of carbon farming, including forests and agroforestry.

Climate Cleanup does not sell trees or plant them for you. We started Oncra, which certifies nature-based carbon removal on land, at sea, in rock and in buildings. Each certificate stands for one tonne of CO₂ removed, calculated from measurements on site, and listed on a public registry. If you want to fund real removal, that is where to look.

Go deeper

Trees are one of many ways nature takes carbon back. See the whole picture.

Nature-based solutions Carbon removal, explained What we do

Sources

2006 IPCC Guidelines, Volume 4: Agriculture, Forestry and Other Land Use (IPCC, 2006)
Restoring natural forests is the best way to remove atmospheric carbon (Lewis et al., Nature, 2019)
Tree planting in organic soils does not result in net carbon sequestration on decadal timescales (Friggens et al., Global Change Biology, 2020)
Mapping carbon accumulation potential from global natural forest regrowth (Cook-Patton et al., Nature, 2020)
Regulation (EU) 2024/3012, the CRCF (European Union, 2024)
Oncra registry (Oncra)

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