Redwoods and carbon

Giant redwoods are among the most effective carbon stores in the living world. They grow quickly, live for a very long time, and lay down enormous volumes of dense wood — so a single mature tree can hold tens of tonnes of carbon in its trunk and limbs. Coast redwoods and giant sequoias do this better than almost any other tree.

Britain's place in this is unusual. Most of our largest redwoods were planted in the 1850s during the Victorian planting craze, which makes them around 150 to 170 years old — young for the species, and only now entering their most productive century. The country holds an unusual number of these mature specimens for somewhere so far from their native range.

It is worth being honest about the limits of the carbon claim. Almost every "this tree stores X tonnes of CO₂" figure is an estimate, derived from girth and height using growth models — not a direct measurement. A single tree's store is small set against national emissions, and a redwood is better understood as a long-term store and a way to get people to care about trees than as a climate solution on its own. We record measurements with a date and a source, flag the ones that are old or approximate, and try not to inflate the number.

Where we have a girth or height for a tree, you will find it on the place record, with the source behind it. See Measuring trees for why those figures need careful sourcing — and if you have a dated measurement we are missing, add it.