Replanting the Port Hills post fires a lesson for all New Zealand


So, the fires that burned with unbelievable fury a few weeks ago, are out. The hot spots are cold and the weekend rain that has totalled nearly 50mm since Friday night has soaked its way into the soil. But as we look forward to the future, questions arise about how we can prevent such an emergency happening again, and what role managing nature can play in it.

The fires that caused, what for New Zealand was a virtually unprecedented fire emergency both in terms of the scale of the emergency services response and the damage, were some time in the making. A combination of land use changes, vegetation changes and a prolonged drought ensured that it would be only a matter of time before a major blaze broke out and consumed property.

A few days after the major blaze, with many hot spots still around and people nervous about the prospects of them flaring up, I attended an open day for the Styx Living Laboratory Trust to look at the revitalization of the Styx River. At one of the exhibits, I was handed a brochure based on research that had been done on the New Zealand native vegetation types and their flammability. It was not lost on myself or the volunteers at the open day that I spoke to about how the vegetation types could have provided fuel for the fires and how this would be a planning issue when the destroyed properties have their future land use determined.

Whilst vegetation is part of the equation when working out the potential fire hazard in the area, there are other factors that need to be considered. These can include things such land use, the types of infrastructure and whether or not flammable materials are stored appropriately. The land use covers, not only the buildings/dwellings on a property, but whether or not it has features such as fire breaks (uniform gaps between vegetation (usually trees) and buildings.

There is one factor though that is somewhat less controllable and that is the climate. Canterbury had been experiencing a prolonged drought through 2015-2016, which had reduced ground water levels significantly across the province and many areas were on heavy restrictions long before a total fire ban was announced just days before the Port Hills fires started. It is also by no means the first fire to break out on the Port Hills. Fires have broken out on the Port Hills several times in the last three decades, but have been brought under control within a matter of hours.

Given the number and geographical distribution of scrub fires across New Zealand, this is an important planning issue. The Christchurch fires demonstrated the potential for property and lives to be lost if steps are not taken to address the land/vegetation use on properties and land owners are not educated on how they can reduce the risk.

It is important to also acknowledge however that all of this somewhat meaningless if an act of arson is involved by someone deliberately setting out to start a fire, especially if lit when it is known that the fire risk is at a dangerous level. Many suspect that one of the fires that started on the Port Hills on 13 February 2017 was deliberately lit, based on time it started and proximity to an established fire.

With common sense, New Zealand will be paying attention to the debate in Christchurch and Canterbury about how replant because there are lessons to be learnt if we are to avoid a Christchurch type emergency happening again.

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