(Credit: D. Geddes, FENZ)
As reported in a previous blog, Scion’s fire team along with its research collaborators from the US Forest Service, San Jose State University and the University of Canterbury, and staff and volunteer firefighters from Fire Emergency New Zealand, Department of Conservation and local communtiy, was able to complete a series of burns in gorse scrub fuels in the Rakaia Gorge in Canterbury in early March.
Six 4 ha research burns were successfully conducted over three burn days from March 2 to 9, with the research team being able to capture data in high and low wind conditions.
Each burn block contained a myriad of instrumentation, ensuring these were some of the most heavily instrumented experimental fires conducted to date. This included 30m tall towers carrying sensors to monitor wind turbulence and the vertical temperature profile within and above the spreading flame front, as well as loggers across the burn area to record rates of fire spread, heat transfer and flame size. Each burn was also monitored with in excess of $1 million of specialist high-speed visual and infra-red cameras on the ground, inside the fires, and monitoring the fire’s progress from above on unmanned aerial vehicles.
With heavy fuel loadings, gorse is known to burn hot. But the temperatures in the research burns surprised even experienced members of the research team. An infra-red camera on a drone above the burn burns reached the upper limit of its sensing capabilities at around 940°C. In-fire 360° cameras blistered as the water that was supposed to keep them cool boiled off, and data loggers melted inside well-insulated housings. Temperatures in the centre of the fires were recorded to reach almost 1,500°C.
The burns were highly successful, and the research team is now analysing the terabytes of data and video footage from the burns ahead of beginning preparations for the next phase of burns in standing wilding pines.
The burns also generated plenty of media attention, featuring on TV3’s Newshub, in the Otago Daily Times (including The South Today video), and in the local Ashburton Courier newspaper and online edition.