Abstract
Smouldering wildfires propagate slowly through surface and subsurface
organic layers of the forest ground and severely affect the soil,
producing physical, chemical and biological changes. These effects
are caused by the prolonged heating and the large loss of soil mass
but poorly documented in the literature. A series of smouldering
experiments with boreal peat have been conducted under laboratory
conditions to quantify these effects using small-scale samples. Peat
samples of 100 mm by 100 mm in cross section and 50 mm in depth of
different moisture were exposed to an external ignition source. Thermocouples
placed throughout the sample bed measured the temperature evolution
and tracked the peat ignition, intensity and spread of the smouldering
front. The results show that moisture content controls peat ignition
and that moisture contents below 125% (in dry base) are required.
The severity of the smouldering peat on the soil has been quantified
in terms of temperature vs. residence-time curves and mass loss.
The measurements show temperatures in excess of 300 °C for residence
times of 1 h leading to sterilization of the soil and mass loss in
burnt layers above 90%.
Users
Please
log in to take part in the discussion (add own reviews or comments).