The boom-bust cycle answer I took for my question:
Sustainability of Regular Global Wildfires due to Oxygen Rich Atmosphere
pends on the atmosphere being rich in oxygen but poor in CO2. I, however, would like the biosphere of is world to be comparable in mass to that of earth, so the total amount of carbon on the planet's surface should be similar to ours.
How can I get plants and animals to keep the majority of the carbon trapped in plants/plankton?
Obviously, this system backfires (literally) for the plants every wildfire/oceanic die-off, but why/how would the plants keep all the carbon to themselves without animals just releasing it all immediately?
I thought about their equivalent to cellulose being a very carbon-dense polymer that uses little water, but I wouldn't know what polymer to use or how that would work.