Figure 5: Adaptation of the intermediate productivity-fire
activity hypothesis as drawn from Ellis et al. (2022) using a) the total
underlying represented area (M km2) of the Earth’s
surface, b) the mean underlying ecoregion flammability threshold (EFT)
and c) the mean underlying inflection point slope estimate (i.e., 1 /
ϕ3). Solid vertical lines in all figures highlight the
25th, 50th, and
75th percentiles of global net primary productivity
(NPP) for all ecoregions with identified EFTs, roughly illustrating the
range of intermediate productivity most associated with fire activity
(~1.2 – 5.4 t C ha-1year-1); points in c) represent the mean location for
biome-level NPP and fire activity indices, highlight that most
ecoregions are, if not within the intermediate productivity range, near
it.