The element of carbon is cyclical and that living things (especially plants and soil) can capture carbon and store it in their biomass (living wood, living leaves, dead logs, dead leaves, etc). Compost and organic-matter found in fertile soils is carbon rich, because it’s full of dead stuff – dead stuff which was made out of carbon.
Calculating how much carbon a tree can capture and store (sequester) throughout it’s lifetime has been increasingly estimated by governments, universities and environmental organizations. These estimations are translated into carbon calculations. A large tree (over 60 feet tall) at 30 years can capture more carbon than a smaller-port tree (between 25 and 59 feet tall). And even smaller plants capture less carbon because they contain less wood, less biomass and thus, less carbon.
Although trees capture huge amounts of carbon, perennial grasses which are maintained with ruminant animals (like cows, goats or llamas) actually capture more carbon because of the biological processes of perennial grasses. Whenever grass (leaves) are eaten, perennial grasses slough off an equal amount of biomass below ground (meaning their roots cut off an equal amount of carbon below ground, after getting chomped-on above ground).
This is why the great plains states, like Iowa and Kansas have up to 90 ft of topsoil – because these vast perennial grass dominated plains had ruminant animals like horses, zebras and camels all chomping away at these perennial grasses for millennia.
The trees planted on Sunset Boulevard will likely capture over 500 tons of atmospheric carbon over the next 30 years. Additionally hundreds of yards of mulch will be placed around the newly planted trees to build soil organic matter, increase soil water retention capacity and capture carbon into the living soil.