Fig. 2: Fire effects on lab-burned soil cores.
a, Thermocouple temperatures at the organic–mineral soil interface (top panel) and 1 cm above the core base (bottom panel) during the 5 h following the initiation of the burn treatments (n = 19 moist soil burn, n = 19 dry soil burn). Burn simulations were initiated at time 0. Temperatures greater than 100 °C suggest the presence of flaming combustion and are not a quantitative measure of soil matrix. b, Soil pH (left) and C:N (right) across soil horizons n = 18 for all O horizons, n = 10 for unburned mineral horizons, n = 11 for moist burn mineral horizons and n = 12 for dry burn mineral horizons. c, Coefficients for two-pool exponential decay models fit to soil C respiration data (R2 of models 0.98–1, P < 0.0001; n = 18 for unburned and moist soil burn cores and n = 19 for dry soil burn cores). Fractional size of the fast (M1) and slow (M2) C pool (left two panels) and decay rate coefficients for the fast (k1) and slow (k2) C pool (right two panels) across burn treatments for the 5-week fast-growth incubation. d, Concentration of total DNA (left) and RNA (right) extracted from soil 24 h post-burn (n = 19 for O horizons for all burn treatments, n = 11 for unburned mineral horizons, n = 12 for moist burn mineral horizons and n = 13 for dry burn mineral horizons). For all boxplots, different letters represent statistically significant treatment differences based on ANOVA and Tukey’s HSD (P < 0.05). The central horizontal line indicates the median, the upper and lower bounds of the box indicate the inter-quartile range (IQR), the upper and lower whiskers reach the largest or smallest values within a maximum of 1.5 × IQR and data beyond the whiskers are indicated as individual points.
