SPECIAL FEATURE: FOREST FIRES

Forest fire fighting challenges challenges

Story: Murray Dudfield, Forest Fire Advisor

NEW ZEALAND IS NOT SHIELDED FROM PERIODS OF

extreme wildfires generally associated with Australia or North America. The annual average direct financial impact of unwanted forest and rural fires on New Zealand's economy in 2020 was $142 million, with indirect costs estimated to be at least two to three times this.

To suppress unwanted fires within a forest landscape, the forestry industry has access to heavy machinery used for harvesting, road building/maintenance, and the formation and maintenance of fire breaks. This equipment becomes a valuable resource and an effective means to assist in the containment of any unwanted forest wildfires. Within this environment, the fire suppression equipment technology trends have changed little over the last 50 years. Forestry resources such as bulldozers, diggers, forestry crews, 4x4 fire tankers/vehicles, etc, remain as a practical in-forest resource for the tasks associated with the containment of fires which threaten the forest environment.

During initial and extended attack scenarios, tasks performed include direct and indirect tactics, fire breaking, mop-up, rehabilitation and hazard reduction. The forestry industry also has a workforce of more than 3,000 persons engaged in forest management, planting and silvicultural work. The majority of this forestry workforce are trained in forest firefighting and hold the required skills and awareness for safely working within and around a tall timber environment.

Incorporating aircraft

Over the past five years, there appears to be a trend that aircraft are becoming the leading tool in suppressing unwanted fires in our forest and rural landscape. With this increase in aircraft comes a threefold increase in expenditure to fund the costs of aircraft. Is this noticeable change the best use of resources in the containment of our future unwanted vegetation fires? To help understand the use of aircraft in forest fire management perhaps an awareness of the past and recent history would be useful.

The first aircraft used in New Zealand for forest fire management purposes was in a surveillance role at the Eyrewell Forest fire in 1943. Planes were first routinely used for fire patrol duties in the Rotorua district in 1943. Early in 1944, very dry conditions prevailed, and the haze and smoke caused assessment difficulties. Given the prevailing fire danger conditions, the New Zealand Air Force provided an aircraft to the New Zealand Forest Service for general patrol duties and an Oxford aircraft, later replaced when a Harvard was assigned for this purpose. It was based at Rotorua Airport and flew with a Forest Service officer as an observer. At this stage, there was no radio on board that could communicate with Kaingaroa Forest HQ, and reports were phoned through after landing.

Following the Second World War, there were plenty of ex-military pilots and planes. Aerial top dressing of fertiliser became established

Forest fire fighting

in New Zealand's rural areas. A newspaper article claimed that the first water bombing trials in the South Island were undertaken at Lincoln in January 1956. The trials were sponsored by the Soil Conservation and Rivers Control Council with the cooperation of Canterbury Agriculture College. Ground crews ignited simulation fires in a fallowed field at the college, and two aircraft from Auster Air Services flew from an area adjacent to the burn site. The fires were in straw and pine branches, laced with diesel and with light wind. One of the planes was a Taylorcraft plane (360-litre water load), and the other a Tiger Moth (180 litres). The aerial attacks were not quite as effective as had been hoped. Most of the observers thought that aircraft use had possibilities, but there was a lot to learn.

The adoption of helicopters for aerial firefighting coincided with their use in the deer recovery business. The early helicopters used were small with limited load capacity but sufficient for the 500 litre buckets. Only the Air Force had Iriquois – Hueys of the Vietnam War – capable of loads up to 1800 litres; however, they were used infrequently at wildfires. As the use of helicopters increased, the bulk of aerial firefighting was from private companies. Indigenous forest logging saw the introduction of heavier machines such as the Iroquois UH-1 and Russian Mil Mi-8, but Jet Rangers, Eurocopter AS350, and BK-117's were becoming the most common types for use in firefighting. The larger machines facilitated development in Above: Mount Cook Station Wilding Pine fire, January 2008. Below: Logging site fire (Photographer: Peter Houston).

Main and inset: Mount Cook Station fire, 2008.

underslung buckets with greater capacities. The air-operated fiberglass buckets (BA cylinders had to be carried to drive the solenoid plunger) had given way to electrically-operated collapsible fabric buckets. The use of fabric reflects the original intent of the Forest Service in 1969. These days, buckets are usually either the Bambi or purpose-built air-operated buckets. Modern buckets can be compressed or folded for easy cartage by the responding helicopter, along with onboard Class A foam injection equipment. The helicopter companies generally own buckets and foam equipment and they are sized appropriately to the helicopters supplied. Of course, costs have escalated far beyond $100 an hour in 1970. A 1996 study by fire researchers from the Forestry Research Institute/SCION showed that bigger was better in terms of dollar cost/litre delivered. The researchers undertook several trial projects throughout 1996/97 to provide guidelines in the use of helicopter water bombing.

Ongoing research in New Zealand and overseas has shown that aircraft used in the initial attack phase of a wildfire can be very effective. However, following the initial attack phase, aircraft become less effective as a wildfire area increases between water drops. When the containment of a wildfire fails in the initial attack phase, ground crews will backburn, use bulldozers to clear firebreaks, crew hose lines, or hack away combustible biomass in advance of the coming flames to starve and contain them. Fireline construction is grueling, necessary, and practical work—but it makes for lousy television. “For sixty years now, the sign of active fire protection has been an aeroplane dropping retardant or a helicopter dropping water,” says Stephen Pyne, a professor of history at USA Arizona State University and the author of over two dozen books on wildfires. "The public expects it." Some informed commentators also have a term for the unnecessary use of aerial resources to fight wildfires: "The CNN drop".

Role of climate change overestimated

As part of this article, it is timely to mention climate change and its fire management impacts on the New Zealand forest and rural landscape. Global temperatures are slowly increasing, and the need to reduce carbon emissions is an ongoing challenge for us all. Associated with climate change is the number of recent public statements which have suggested that our summers in New Zealand will become drier and fire seasons are becoming longer. They also indicate that climate change will see more severe fire danger conditions for New Zealand and could lead to a more significant number of larger, more extreme wildfires. To understand whether fire danger levels in New Zealand are likely to increase over the next 20 years, a research project on this question was undertaken in 2020. The published Impact of Recent Climate on Fire Danger Levels in New Zealand report clearly shows this research does not support such statements. These

Fire danger sign.

conclusions were based on trends from up to 60 years of historical weather data from 15 weather sites across New Zealand. The following links provides access to this report to provide readers with a better understanding of the data and evidence presented in this research: https://www.nzif.org.nz/assets/Uploads/ Impacts-of-climate-on-fire-danger-levelsin-NZ-Feb-2021.pdf https://www.nzif.org.nz/assets/Uploads/ Overview-Graphs-Tables-15-RAWS-Final.pdf.

In addition our maritime climate significantly impacts the New Zealand forest and rural landscape when compared with Australia. Research has indicated a likelihood of more rainfall in the future across eastern parts of New Zealand.

Media reports have stated that by the year 2040 fire risk levels are projected to increase by 70 percent. However the 2020 Impact of Recent Climate on Fire Danger Levels in New Zealand Report findings indicate it will take a significant swing in current weather patterns to suggest that the average annual frequency of elevated fire danger levels across New Zealand will increase dramatically over the next 20 years. Timberland forest fire truck.

A return to ground?

As fire danger levels in New Zealand remain stable, is the increased use of aircraft more wildly used at wildfires becoming the norm in New Zealand, or should we return to greater use of fire crews and heavy earthmoving machinery?

The past five years have seen more and more aircraft deployed to wildfires. For example, on days two and three of the 2019 Tasman wildfire in Nelson, we saw 22 helicopters and two fixed-wing aircraft in use at this wildfire. To the casual observer, it may appear that fire managers are committing more resources to

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fire suppression. However, the ratio of air-to-ground resources seems out of balance as a successful and efficient fire suppression strategy. Reported media comments on the 3rd January 2018 wildfire at Roys Peak near Wanaka saw eight helicopters and only five ground crews involved for a 200-hectare wildfire. In addition, a small fire incident that occurred in an area of scrubland adjacent to the State Highway, 40 kilometers north of Kaikoura, on 7th July 2021 is a further example. This winter fire involved four helicopters deployed to assist a small number of firefighters when fire danger levels were low. The four helicopters arrived on the fire site more than five hours after the fire started.

Expenditure in New Zealand on aircraft has increased threefold in the past four years (Figure 1, right). Given the separated accountabilities of the National Rural Fire Authority (NRFA) and regional Rural Fire Authorities before July 2017, the critical role the NRFA had was as a gatekeeper and ensuring fire expenditure incurred by Rural Fire Authorities remained fair and reasonable. Following this assessment, 90% of the fire suppression costs involved were reimbursed to Rural Fire Authorities from a national fund. With a single fire service entity now in place for New Zealand, a key question remains as to what entity is playing the independent gatekeeper role to ensure the productivity and value for money aspects for the management of wildfires in the forest and rural landscape are delivered. The February 2019 Tasman wildfire saw the aircraft cost involved as the most expensive in the history of wildfires in New Zealand. Research for another day could look at the background to this threefold increase in aircraft use at wildfires over the past four years.

It is also interesting to note that even with an increase in the use of aircraft deployed to wildfires for the past four years, the three-year average area burnt, due to unwanted wildfires, has also increased (Figure 2, right).

Are we too reliant on aircraft?

Comments from several experienced fire managers on their observation on water dropped from aircraft, without the necessary support of sufficient machinery, ground crews with pumps and hose lines, have raised an uneasiness with the management of wildfires. Their impact assessment for water dropped from helicopters was estimated as less than 40% effective, whereas heavy equipment and the practice of water delivered through a ground crew and hose line is more than 90% effective. Are we becoming too reliant on aircraft attempting to put out wildfires?

To review an example of the suitable mix of ground and aerial resources in firefighting an assessment of several wildfires in the USA was compared with New Zealand. To make a comparison between New Zealand and the USA this assessment included only USA wildfires involving areas of less than 6,000 ha. For New Zealand, covering a four-year period from 2015 to 2019, an assessment of eight wildfires showed an average ratio of 8.0 firefighters per aircraft. For USA, involving sixteen 2019 wildfires, the ratio of firefighters per

Figure 2

Mount Cook Station fire crew briefing.

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Above:

1. Forest fire water supply; 2. Mount Cook Station firefighter; 3. Forest fire depot hose store; 4. 1942 Quad forest fire truck.

Below: Firebreak and hose lay (Photographer: Peter Houston).

aircraft was 94.9 (Figure 3 above). The results of this study show a huge difference in the levels of ground firefighter resources deployed at similar-sized wildfires in the USA when compared with New Zealand. Aerial firefighting is also a risky business. In New Zealand, over the last eight years, four helicopters have crashed due to firefighting activities. This resulted in three fatalities. It's a risk taken that many believe is far too frequent. Aerial firefighting – by helicopter or fixedwinged aircraft – has inherently higher safety risks than ground firefighting. It is also expensive, can be regularly misused and, as some experts argue, is symbolic of a misguided approach to fire policy. While firefighters and fire researchers agree that "the aerial attack" can be an essential component of an effective firefighting strategy, its imprudent use can come at a steep financial, ecological, and human price. And for that, we, the public, might bear some of the blame. Without sufficient experience and field-hardened firefighting crews working alongside ground machinery, having a heavy reliance on aircraft to suppress our unwanted forest and rural fires is like steering a boat without a rudder.

Though fighting wildfires from the air may seem miraculous, it is no godsend. If aircraft are overused, it is because citizens, perhaps too often, expect them to show up and perform the impossible.

About the author: Murray Dudfield served as the New Zealand National Rural Fire Officer from 1990 to 2014. He was awarded an FAO Certificate of Excellence for exemplary service to International Cooperation in Wildland Fire Management in 2014 and appointed an Officer of the New Zealand Order of Merit in 2015. Murray was a board member of the Australia Bushfire Cooperative Research Centre from 2007 to 2014 and a Board member of the Otago Rural Fire Authority from 2014-2017. He is a Fellow member of the New Zealand Institute of Forestry and Chair of the Institute’s Forest Fire Committee. NZL

Pigeon Valley fire site visit.