Six months on – a Port Hills fire re-grassing update

Half a year on from the devastating Port Hills fires near Christchurch, a green tinge covers what had been scorched earth

Drone re-seeding the Port Hills near Christchurch after fires

Sadly, over winter with extremely bad, wet weather, a lot of soil moved and gullies which were covered in gorse and broom for over 30 years were exposed to the elements, meaning that not all re-seeded areas were successfully established. Settling into early spring, the mixes that were applied in the protected areas have successfully surpressed the gorse and are providing ample feed supplies for cattle to graze. More importantly, it helped slow the sediment run off over the wet winter months, which had been a key concern.

Earlier this year following the fire, Dr. Peter Klaassen (GM Sheep, Beef and Horticulture at Craigmore) having seen the devastation caused, took advantage of the opportunity to use his skills and networks to help individual landowners and the wider community. Peter took on the role of coordinating the process of re-seeding the burnt land. He sourced advice and seed, and was instrumental in obtaining helicopter and drone time. There was a great response from companies willing to give time and materials either for free or at a reduced price.

That re-seeding programme had a clear focus – to suppress the gorse before it re-established. Aside from the areas which had a large subterranean clover seed-bank in the ground, many of the gullies had been covered in gorse for decades, so other than gorse seed, there was very little seed in the ground. Getting grasses and clovers established would suppress the gorse or force it to elongate, making control easier.  The seeds Johnston supplied were a mix of fast-growing or short-rotation grasses, subterranean clover and the perennial pasture plant cocksfoot. Fortunately, that timing was perfect and around 450ha was sown, the majority carried by helicopter, but a drone also played a role in sowing some smaller areas. Peter approached Yamaha and they transported their agricultural drone down to the valley. In what was something of an experiment, the drone, capable of carrying 15kg or one hectare’s worth of seed, proved its worth broadcasting seed onto smaller areas. This highlighted the potential role drones could play in the agricultural industry.

Landowners were encouraged to review Craigmore’s sustainability principles to reduce the possibility of future events.  By addressing risk management, sustainability and community values the community could better understand how to manage their environment. Dr. Peter Klaassen still believes livestock, particularly cattle, will have an important role to play in controlling gorse within the newly sown pasture. Cattle will graze young gorse seedlings as part of the pasture sward and are excellent to controlling long grass and preventing the build-up of desiccated vegetation which literally becomes fuel for the fire.