akar.earthLitter: Definition
What is litter in forest carbon accounting? Definition of the litter pool, how it is sampled, and why most Indonesian projects treat it as optional.
Litter is the carbon pool of non-living organic matter lying on the soil surface above the mineral or organic soil, such as fallen leaves, twigs, fruit and fine woody debris below the dead-wood diameter threshold. It is one of the five IPCC forest carbon pools.
Why it matters
Litter links the trees to the soil. It is the main route by which carbon from leaves and twigs enters soil organic carbon, and it protects soil from erosion and heat. In carbon accounting, though, it is usually a small pool compared with biomass, and it turns over quickly in warm, wet tropical climates.
How it is measured
Field teams place small frames at systematic points inside plots and collect all litter within them. Samples are oven-dried and weighed, and sometimes analysed for carbon content. Results are scaled to tonnes per hectare. Because litter varies with season, re-measurement should happen at the same time of year. The boundary with dead wood is set by a diameter threshold (often 10 cm), and the boundary with soil by a defined layer.
Most methodologies treat litter as optional. Projects can exclude it if the project activity is not expected to reduce it. Our carbon pools guide explains conservative exclusion.
Indonesia angle
In humid Indonesian lowlands, litter decomposes fast and the standing stock is modest. In peat swamp forests, the line between litter and peat is blurred, so projects must define layers clearly. In mangroves, tides wash much of the litter away. For agroforestry and ARR on degraded land, litter usually increases as canopy closes, but the gain is small and rarely worth the sampling cost.
Common mistakes
- Sampling in the dry season at baseline and the wet season at verification.
- Mixing fine roots or surface peat into litter samples.
- Including litter where site preparation, such as burning, removes it.
Related terms
See dead wood, soil organic carbon and carbon pool. The forest carbon hub covers how pools fit together.
Frequently asked questions
How is the litter pool measured?
Collect all litter inside small frames (for example 0.5 m × 0.5 m) at sample points, dry and weigh it in a lab, then convert dry mass to carbon.
Is litter usually included in carbon credits?
Usually not. Litter is a small, fast-changing pool, so most methodologies let projects exclude it if exclusion is conservative.