Fig. 2.

Conceptual scheme of the balance (ratio) between biomass burned (RegBB) and fire frequency (RegFF), defining fire size and their relationships to climate conditions and orbital forcing. We deliberately oriented relations of cause and effect, using arrows from the relationships established using the correlation coefficients presented in Table 1. Signs (colors) refer to significant positive or negative correlations, respectively. During the Holocene, the FS index has moved along the scale from values <1 to values >1 (Fig. 1C) and it stopped twice around a value of 1, owing to different conditions.