The connection between wildfires and spatial design
Landscape architects are being urged to consider wildfire risk factors when designing and planning, as climate change increases the fire threat level. Lincoln Masters graduate Steffan Kraberger has just finished his thesis looking into the connection between wildfires and spatial design, and he believes that both the Nelson fires and Canterbury’s Port Hills in 2017 are a part of New Zealand’s increasingly wildfire-prone climate.
A study by the Crown Research Institute Scion predicts New Zealand’s fire risk could double - possibly even treble - in some areas like Nelson. That’s because of higher temperatures and decreased rainfall. Stronger winds and lower humidity are also contributing factors. Scion’s rural fire research team warn “extreme fire is here. With 2015 and 2016 globally the warmest years on record, New Zealand is not immune to the extreme fire behaviour normally associated with Australia, North America or the Mediterranean. The 2017 Port Hills fire is an example of this.
But Kraberger says landscape architects are in a position to help manage this increasing wildfire threat. “Landscape architects should be thinking about where things are likely to be located,” he says. “The vast majority of fires in New Zealand are man-made. So we need to think about land uses, what’s allowed to be located where and what wildfire implications that may have; what we plant and where buffer zones should be placed.”
For example, he says our expanding suburban and lifestyle areas should be avoided or buffered alongside Pinus forestry blocks, as the combination of these land uses brings together extensive areas of highly-flammable fuels, with a concentration of possible ignition sources and property that would be affected if a wildfire was to occur.
He also pointed to the country’s “massive road reserve. If they are covered in long grass, that increases the likelihood of a wildfire happening. Whereas if it was a broadleaf native plants like kapuka, taupata, or harakeke flax, plants with low flammability, if an exhaust spark lands on the verge the likelihood of the foliage igniting is much lower. And if it does start burning, the burn is much slower. Whereas with dry grass you’re increasing the likelihood of a wildfire.”
To that end LAs need to be mindful of how highly-flammable plants are used or encouraged, such as Kanuka and Ake ake. Similarly, the retention of woody-weeds such as gorse to allow native succession is a process which retains highly flammable fuels for one to two decades, so could be tactfully buffered.
Kraberger used the peri-urban Port Hills fires in 2017 as a case study for his thesis. He found that compared with international management of wildfire threat, land management strategies such as emergency response had been effectively developed, social strategies such as education are developing, while spatial planning has been comparably ignored as a strategy to manage this ongoing threat.
Kraberger says “one of the main solutions in my mind is how to use our fuels and our land covers as buffers between problematic land-uses, and how this might overlap with other objectives such as conservation. New Zealanders have to accept that wildfires will be a common part of New Zealand life. We’re not going to completely eliminate the possibility of them occurring so we have to focus on how to manage their effects in a much more long term way.
“I don’t think landscape architects have considered wildfire enough, firstly to manage the issue but also by not doing so we can perpetuate the wildfire problem”.
FOOTNOTE: On Tuesday, February 5 two separate fires began burning in the Tasman and Nelson district 20 kilometres apart. The biggest, the Pigeon Valley fire, ripped through more than 2335 hectares within a 33 kilometre perimeter, making it one of the largest fires in decades. A state of emergency was declared the following day as authorities began evacuating people.
At its height, 22 helicopters were tackling the Pigeon Valley wildfire, which caused 3000 people to evacuate their homes and destroyed one house. It is New Zealand’s largest aerial firefight on record.