Soil carbon is climbing on the year-three plots

Soil samples from plots planted in 2022 in the Kenya Highlands show measurable gains in soil carbon. That is the slow half of the drawdown story, the half that usually takes years to show up at all, so seeing it this early is worth recording carefully.

Most of the carbon a young forest captures is in the wood you can see. A growing tree pulls carbon out of the air and puts it into trunk, branch and root, and that is the part that shows up first and is easiest to measure.

The carbon going into the soil is slower and far harder to track. It builds as leaves fall, roots die back and the soil life works that material in, and it moves at the pace of decades rather than seasons. But it is also more stable, because soil carbon does not burn off in a fire or rot away in a single bad year the way standing wood can.

Measuring it is laborious. It means cutting soil cores at set depths, drying them, and running them through a lab, plot by plot, then comparing against bare control ground that was never planted. Dr Amara Okonkwo's team has been strict about the sampling so the comparison actually holds.

Three years in, the soil under the oldest plots is holding measurably more carbon than the bare control ground beside it. The gain is small in absolute terms, and we are not going to inflate it into a headline figure it cannot support.

But it is the part of the carbon story that lasts the longest. Wood can burn. Trees can die. Carbon worked deep into the soil tends to stay, which is why this slow, unglamorous number matters more than its size suggests.