Scion fire scientists and Fire and Emergency New Zealand are carrying out controlled fire experiments on gorse in the Rakaia Gorge, near Methven in February/March 2020.

Why are you deliberately lighting fires in light of the Australian bushfires and the current extreme fire risk?

Wild fires and bush fires can be devastating. Every year in New Zealand, around 3000 wildfires burn some 6000 hectares of rural lands. We want to understand how fires behave in various fuel and weather conditions so fire agencies and land managers can manage the serious risks posed by wildfire, including loss of life and property.

This study will provide us with valuable data that can be used to develop improved fire behaviour models and prediction tools for rural fire managers.

It will help fire managers predict where fires are likely to occur, how severe they will be, how they are likely to behave based on vegetation type and other conditions, and what resources are needed to control them and put them out.

It will provide important data on fuel loadings, fire spread rates and smoke behaviour for gorse vegetation, a highly fire-prone fuel type common across the country, that will aid understanding of fire behaviour in scrub fuel types for use in improving training information and prediction tools for firefighters and rural land managers.

What vegetation are you burning and why?

These burns will be carried out in 1-2 m high mature gorse.

This study will provide us with valuable data that can be used to develop improved fire behaviour models and prediction tools for rural fire managers. Specifically, the project aims to test the hypothesis that convective heat transfer via the movement of fire-heated air plays a more dominant role in fire spread than previously thought via just radiation.

We have carried out experimental burns in crop stubble fields to explore this fire behaviour in controlled, uniform, low fuel situations. Now we want to gather information on how fire burns through more complex scrub fuel types. Mature gorse is particularly interesting as it can contribute a heavy fuel load to fire and burn intensely.

Is it public or private land you are burning on? Who gave you the approval to burn this land and vegetation?

The area of gorse to be burnt is on a mix of private land and Land Information New Zealand (LINZ)-managed land near Rakaia Gorge, Canterbury.

Permissions have been obtained from Land Information New Zealand. We have also obtained consents from Environment Canterbury and Department of Conservation for the research activities, including fire breaking and vegetation clearance.

A fire permit and approvals for the burns have been issued by the Fire and Emergency New Zealand. Conditions imposed in the fire permit include restrictions on the weather conditions under which the burns can be lit, and the requirement to have fire crews and equipment onsite during the burns.

How long are the burns going to take?

Six burns of 3-4 ha in size are planned over four to five days within an 80 ha area. Each burn will take about one hour, and a maximum of two burns will be completed on any burn days. Burnouts to remove vegetation fuels in areas adjacent to the research burn blocks will be conducted in the weeks prior to the main experimental burns, to reduce the chances of these burns escaping.

Weather and fire season conditions permitting, the burn-outs will be completed during the last two weeks of February (17-29 February 2020), with the main research burns occurring during the first two weeks of March (1-14 March 2020).

Why is wildfire research important?

Every year in New Zealand around 3000 wildfires burn some 6000 hectares of rural lands with an annual cost to New Zealand of around $100 million per year. This figure includes firefighting response and readiness costs, and immediate damages to property. However, it does not include the equally devastating downstream or indirect losses associated with damage to rural lands or conservation resources, and personal property and lives, which can equate to many times the direct costs.

The economic, social and environmental costs of wildfire are growing, and will continue to grow as communities increasingly spread into rural and forested areas, and as the changing climate results in hotter, drier conditions and an increasing number of extreme fire-risk days.

What are the difficulties associated with this research?

The main challenge with experimental burns is getting the right weather conditions to safely and effectively conduct the field work. For example, conditions may be too dry or windy to bun safely, or too wet and calm to burn effectively.

This project is supported by strong collaborations with a range of agencies that remove most of the difficulties associated with research of this kind.

What specific measures have you taken to keep the fires under control? For example, you can’t control what the wind will do?

We have planned well. All necessary permits and approvals have been obtained for the fires, and every precaution is being taken to ensure that the fires are contained.

We are working in conjunction with Fire and Emergency New Zealand and DOC, as well as the landowner, neighbours and wider community, to ensure these fires remain under our control.

Fire and Emergency New Zealand and DOC have been actively involved in the burn planning and permitting. Fire breaks at least 10 m wide have been created around the experimental burn area. Firefighters and equipment will be on site at all times during the burns, with a Fire and Emergency New Zealand-led incident management team overseeing both the burn-outs and main experimental burns. Fires will be lit only when the winds and fire dangers are favourable and within fire permit conditions. Weather conditions, including wind speeds, are being monitored onsite via an automated weather station. A helicopter will also be on standby during the burns.

All research and firefighting personnel are trained and experienced. All people entering the burn site each day will receive a full fire operations and health and safety briefing. In addition, a traffic management plan will be in place and air traffic control will be notified in case of possible smoke hazard.
A project communications plan has also been prepared specifying notifications and publicity to be undertaken in the lead up to and during burning.

How do you know the fires won’t get out of control?

Every precaution has been taken to ensure that the fires are contained within the designated area. The fire permit contains restrictions on what weather conditions the fires can be lit under and what firefighting resources must be onsite at the time of the burns.

We are working in conjunction with Fire and Emergency New Zealand, Department of Conservation to ensure these fires remain under control. These agencies are providing firefighters and equipment to keep the burns within the designated area, but also to quickly contain any fire escape should one occur. A helicopter will also be on standby during the burns.

Do these fires pose any threat to neighbouring properties?

We are confident there is little risk of these fires endangering surrounding properties.

The nearest homes are several kilometres from the burn site, but the burn site is adjacent to several farm properties. All neighbouring property owners have been consulted throughout the research planning process to identify important values to be protected and have made visits to the site to see for themselves, the location and safety measures that are in place. They will also be invited to be present when burning takes place.

Measures are in place to keep stock safe, and temporary road closures, access controls and signage will be in place during all burn periods.

The Scion Rural Fire Research team are very experienced and have completed over 140 similar burn experiments in different vegetation types. Four of Scion’s fire researchers are trained firefighters with first-hand experience of fire fighting and front-line fire management.

What danger do these fires pose to native animals and birds?

A detailed assessment of environmental effects was undertaken by independent ecologists as part of obtaining the Resource Consent from ECan, including impacts on both native flora and fauna.

The fire could affect native skinks and geckos. Following the identification of potential impacts on lizards, a Wildlife Permit has been obtained from DOC and a detailed Lizard Management Plan prepared that outlines specific mitigations that will be undertaken to minimise these impacts. This included removing half of the gorse block with the best lizard habitat from the area to be burnt, building rock refuges and berms, and replanting the burnt area after the fire with native species found on the site to improve lizard habitat and biodiversity.

Removing the gorse is also likely to enhance the habitat of native birds that feed and breed in the adjacent braided river environment of the Rakaia River, by removing cover across the area for predators such as wild cats and stoats and ferrets, for which a trapping programme is presently in place.

What are the consequences of not doing this research?

As our climate changes and hot, dry conditions become more common, the numbers and costs of wildfires are likely to increase significantly resulting in greater potential for:

• Loss of life
• Loss of property, including forests and agricultural production
• Loss of flora and fauna for conservation management.

What information will you get from the experimental burns?

These burns will provide data on fire behaviour to develop and improve fire behaviour and smoke prediction tools for gorse and other vegetation fires.
They will also add significantly to the international understanding of heat transfer processes and flame dynamics that contribute to ignition, spread and transition to extreme fire behaviour in rural vegetation fires.

How will this information help?

Our research helps fire managers to predict where fires are likely to occur, how severe they will be, how they are likely to behave based on vegetation type and other conditions, and what resources are needed to control them and put them out.

Scion’s rural fire research is conducted to provide FENZ and other rural fire and emergency response agencies with the knowledge and tools to prevent fires from occurring and to put wildfires that do occur, out more quickly and safely.