Archived content: This media release was accurate on the date of publication. 


Making mini-mud pies, sieving glowing embers and grinding steel seem like hard ways to start a fire, but the results suggest otherwise, says Masters student Heather Wakelin.

Date:  19 February 2010

Making mini-mud pies, sieving glowing embers and grinding steel seem like hard ways to start a fire, but the results suggest otherwise, says Masters student Heather Wakelin.  

Canterbury University student Wakelin is weeks away from submitting her thesis, a joint project with Scion and the Department of Conservation, tackling the issues around fires in high country grasslands. 

“I’ve had to put up with nasty smoke smells for about 3 ½ months but it was a really good experience, and I love lighting stuff on fire - it was way fun!,” says Wakelin. 

“But what’s really exciting is that the results of my research can now be used by fire managers in the field, to help with fire prevention.” 

Wakelin designed five experiments to simulate the sources of fire that have the highest concern for DOC; a hot plate was used to simulate hot exhaust or machinery parts; hot carbon particles out of a vehicle exhaust; organic embers; metal sparks from grinding operations; and an open flame similar in size to a lighter. 

Using two types of grass - an exotic and a native hard tussock - Wakelin varied moisture content and wind speed to test how quickly each source resulted in fire ignition. 

Her findings varied with each experiment, with some significant results for some, and more questions to be answered for others. 

“In the open flame experiment, I found that wind speed had a significant effect on whether or not the sample ignited, but also that at the top speed, it blew the flame out,” said Wakelin. 

“It would be interesting to find out what wind speed would blow a gas cooker flame out, as I believe this is one of the riskiest sources of flame in the backcountry.” 

But it’s the results in the metal sparks and hot plate experiments that have got Wakelin and fire managers excited. 

“The results from the hot metal plate trial suggested that the chance of fire is more dependent on the heat of the metal, (398º or higher) rather than moisture in the grasses,” said Wakelin.

 “This is significant when you put it against what we know about ATV vehicles in particular. ATV manifolds have been recorded as reaching temperatures of up to 585 degrees.” 

Lab experiments were also replicated in the field, at Lake Emma in Hakatere Conservation Park, Ashburton Lakes. 

“In the field we tested two vehicles; an all-terrain vehicle (ATV) Honda quad bike and a diesel Nissan Navara 2006. We drove both vehicles around for 20 minutes then left them in idle while we conducted the experiments. With the ATV all our samples caught fire, but none for the Nissan. ” 

“This park has already had a fire, which DOC believes was started from by a motorbike which had been repeatedly driven up and down hills - which is pretty common behaviour.” 

Tony Teeling, fire manager for DOC in Canterbury says that fire is an ongoing issue in the high country and this project takes the department a step closer to managing prevention.

“Through tenure review, the department has inherited more and more high country grasslands to manage, and with better public access, especially with the rise in all-terrain vehicles, fire is a very real threat. 

“The next step for Heather is to work with Scion to write a technical transfer note, so we can apply her findings to decisions on the ground, such as when to close vehicle access into fire-prone grasslands,” said Teeling. 

“To be able to back these decisions up with sound science is critical. Our job is not just about fighting fires, but preventing them in the first place.” 

“Heather will be presenting a seminar of her findings to the wider fire community in April,” he said. 

This research was a joint project between University of Canterbury, Scion and the Department of Conservation.  It was funded by the Ō Tū Wharekai Wetland Restoration Project (DOC), the New Zealand Federation of Graduate Women, and the Owen Browning Scholarship in Forestry. 

To find out more:

Heather Wakelin is completing a Master in Forestry Science, jointly between the Engineering and Forestry units of Canterbury University. Her official thesis title is: “Ignition thresholds for grassland fuels and implications for activity controls on public conservation land in Canterbury.”

Key contact: Heather Wakelin; 021 02363793

DOC is the largest rural fire authority in the country, responsible for preventing and managing fires on public conservation land, all unoccupied crown land (including crown riverbeds) and within one kilometre of these lands.

Key contact: Tony Teeling, TSO Fire; 027 281 6709

Scion is a Crown Research Institute formly known as the New Zealand Forest Research Institute Limited. One of Scion’s objectives is to translate research outcomes into benefits for New Zealand.

Key contact: Stuart Anderson, Scion rural fire research group; 

This project was partly funded by the Ō Tū Wharekai Wetland Restoration Project, which includes Hakatere and Kahui Kaupeka conservation parks in the Ashburton Lakes district. Ō Tū Wharekai Wetland Restoration Project aims to restore one of the best examples of an unspoiled, intact, inter-montane wetland system remaining in New Zealand, and is nationally important for wildlife. The project includes the braided upper reaches of the Rangitata River, and the 12 lakes that make up the Ashburton Lakes, along with ephemeral turfs, streams, swamps and bogs.

Ironically, wetland vegetation often burns well, particularly in peat bogs and sedgelands. Ash and runoff from a fire can have serious effects on wetland and stream ecology.

Key contact: Kennedy Lange, DOC programme manager biodiversity; 027 4974513.

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