Highly flammable vegetation helps fuel Port Hills fires
15 February 2017
Firefighters have been battling fires on Christchurch's Port Hills since Monday evening.
Hundreds of hectares of scrub and vegetation have been burnt and nearby residents have been evacuated.
The Science Media Centre asked an expert about the conditions fuelling the two fires. Feel free to use the comments below in your reports.
Dr Tim Curran, Senior Lecturer in Ecology, Lincoln University, comments:
"Along with weather and landform, fuel is a key determinant of fire behaviour. In wildfires the main fuel is plants, however, it is important to note that plant species are not all equal when it comes to fire. The biomass (amount of plant material), arrangement (how continuous or connected the vegetation is) and flammability of plants (how well they burn) will determine the behaviour of a given fire.
"In areas with high biomass (particularly dead plant material), continuous vegetation (both horizontally and vertically, so the fire can spread throughout the area and up into the canopy), and highly flammable plants you will get intense fires that burn over a large extent.
"The Port Hills and Banks Peninsula have large tracts of continuous, highly flammable vegetation. This includes scrub dominated by gorse, pine and eucalypt plantations or shelterbelts, pastures and grasslands, and native regrowth dominated by kanuka. Gorse and some pine species retain dead material on the plant which makes them particularly flammable. When combined with hot, dry and windy weather, such vegetation fuels the intense and extensive fires like those we are currently experiencing on the Port Hills."