Researchers found that the best time to ignite preemptive fires was when fuel moisture content the amount of water a fuel holds, expressed as a percentage of its dry weight was close to 120 percent and relative air humidity was between 12 and 79 percent. This was equivalent to between 12 days and one month after the last rain, depending on the site. They also found that the fires' rate of spread was greater when wind speeds were fast and fuel moisture content, relative humidity and fuel load were all low.
Their results showed that a fuel load of 94 grams per square meter is sufficient to support savanna fires in West Africa less than half of what's required for savanna fires to propagate in South Africa. This is likely due to high grass cover and fast wind speeds.
"Fires have long been regarded as the enemies of the savanna, but since time immemorial, they have played a role in keeping these ecosystems functioning optimally, keeping the domination of some species over others in check," said Momadou Sow of the Environmental Sciences Institute of the Cheikh Anta Diop University in Dakar, Senegal. "Until now, we've lacked the accurate scientific knowledge to properly plan early season prescribed fires in West African savannas - our research is a step towards filling that gap."
Wildfires, like the hundreds that ravaged southeast Australia and Tasmania in early January, can cause widespread environmental devastation and destruction of property. Once the infernos gather strength, aided by wind and ample fuel supplies, they become uncontrollable and can travel large distances, destroying infrastructure, wreaking havoc on ecosystems, releasing millions of tonnes of greenhouse gases into the atmosphe
|Contact: Julie-Anne Savarit-Cosenza
World Agroforestry Centre