[mirimir]

That's actually pretty much true. At least, if it literally "vanished", without releasing biomass carbon back to the atmosphere.

In temperate ecosystems, there's net long-term storage of biomass and nutrients in soil. Mainly roots of dead plants. But also stuff that accumulates faster than it can decompose. Tundra and taiga are extreme examples.

But mature tropical ecosystems are pretty much in equilibrium, with ~zero net impact on the soil or atmosphere. Pretty much all mineral nutrients are locked up. And everything that dies gets recycled very quickly.