Prescribed fire increases pyrogenic carbon in litter and surface soil in lowland Eucalyptus forests of south-eastern Australia

• Prescribed fire emits 6.1 Mg ha−1 carbon (C) from the forest ecosystem.
• Fire redistributes C from litter to soil and increases pyrogenic carbon (PyC).
• Net loss of 1.6 Mg ha−1 litter C offset by 1.7 Mg ha−1 C gain in 0–2 cm soil.
• Fire increases PyC by 310 kg ha−1 in litter and 370 kg ha−1 in 0–2 cm soil.
• Net change in litter + soil (0–2 cm) PyC comprises about 11% of fire altered carbon.

Low intensity prescribed fire is widely practiced in seasonally dry forests in many countries to reduce fuel loads and the risk of uncontrollable wildfires. Associated with low intensity fire is the heating and alteration of organic matter of the litter and surface soil to create pyrogenic carbon (PyC). This study reports changes in total carbon (TC) and PyC in the litter (as char particles) and the top 2 cm of soil (as oxidation resistant carbon, PyC) in Eucalyptus obliqua forests in south-eastern Australia. Litter and surface soil were sampled and carbon (C) measured before and immediately after low intensity prescribed fire on the same sites. Post-fire, lightly burnt (FIRE-300) and heavily burnt (FIRE-600) forest floor areas were sampled separately. On average, net loss of 1.55 Mg ha−1 C (10% of initial) from litter was largely offset by increase of 1.67 Mg ha−1 C in soil (which was restricted to the 0–2 cm layer) with no net change in the initial litter + soil C stock of 21.9 Mg ha−1 C. Concurrently, fire increased PyC by 0.3 Mg ha−1 in litter and 0.4 Mg ha−1 in surface soil, which together were equivalent to about 11% of the 6.1 Mg ha−1 C emitted to the atmosphere as a result of the prescribed burn.