Organic carbon is stored in multiple forms in forests: in the soil, in roots, stems, and leaves of forest vegetation, and in associated bacteria, fungi, and animals. This indicator is measure of the amount of organic carbon present.

Fires naturally vary in size, depending on climatic conditions, material available to burn, and artificial control. In a healthy fire-adapted ecosystem, fire extent can frequently be small (a few hectares) and less frequently be large (thousands of hectares). In a less healthy system, for example one which has had fire suppression, small fires may be more common due to suppression, but may eventually escape control and become very large due to buildup of vegetation.

Fires naturally vary in length, with larger fires tending to burn longer. Longer-burning fires may generally emit more smoke and consume more vegetation, as well as potentially consuming more resources for fire control.

Fires naturally vary in intensity, with low-intensity fires burning the underbrush and forest-floor surface and high-intensity fires burning tree stems and crowns. Although crown fires naturally occur and are not necessarily harmful to forest ecology, they cause more change in forest structure than low-intensity fires.

Each vegetation type will have a range of fire recurrence interval, which will be determined by the dominant pant species, geographic location and other factors. If fire recurrence in a place falls outside this range, then the vegetation type may change in type or structure, which may also cause other secondary changes in geomorphology and habitat quality.

The Carbon to Nitrogen (C/N) ratio compares the amounts of these two important solid components. This ratio is indicative of nitrogen limitation in soils, which may limit plant growth.