They're usually busy putting out blazes but yesterday firefighters and scientists spent the day starting them.
It was part of a series of burns in Canterbury to test a new theory about the way wildfires spread.
A group of firefighters lit fires to learn how to predict, train for and mitigate them.
"By understanding the fires we can be better prepared for them," Grant Pearce, a Scion fire scientist told 1 NEWS.
A field had beens laced with sensitive yet fireproof scientific equipment to monitor the way fire moved.
Scientists had a small window to gather their data as the burn ripped through one hectare in just two minutes.
It was to test of a new theory by American fire researchers who say the spread is less about the heat given off by the flames and more to do with the air turbulence it generates.
"If this research is correct it would change the we way we treat and fight fire," Mr Pearce said.
Mark Finney of the US Forest Service said fires are inevitable.
"We have them every year, it shouldn't be a surprise. What we need to understand is how to protect ourselves," he said.
"We can have wildfires we just don't have to have disasters."
The research will take four years and controlled burns could scale up to scrub and eventually pine forests.