– the control of exotic vegetation on Auckland’s volcanic cones

The volcanic cones of Auckland were taken from the Māori about 150 years ago; the cones were and are considered ancestral mountains, they are Tūpuna Maunga. During those 150 years, Māori had little if any say in how the mountains were used or what happened with them. Fourteen of the Tūpuna Maunga have recently been returned to the 13 mana whenua iwi and hapū of Auckland, and now the non-Māori have little if any say in how the mountains are used or what will be done with them. For someone like myself with no people or place association with the mountains of Auckland, it is an interesting and complex situation.

The management and administration of the 14 Tūpuna Maunga has been entrusted to the Tupuna Maunga Authority (TMA). The TMA has been given the guardianship to restore, protect and manage the mountains as taonga tuku iho (treasures handed down the generations), they are responsible for the spiritual, cultural, economic and ecological wellbeing of these ancestral mountains.

In June of this year, Auckland Council voted unanimously to declare a climate emergency. In doing so Auckland joined other Councils around New Zealand and across the world, mayor Phil Goff even went on to publicly acknowledge that “our climate is changing and the time for action is now”.

In response to the emergency, the Auckland Council asked the city to help them develop a Climate Action Framework (the Te Tāruke-ā-Tāwhiri); we need a framework to create a better, climate-ready and zero-carbon Auckland, we need to enhance, restore and connect with our natural environments. We need to ensure that the custodianship of mātauranga Māori knowledge systems, practices and the teachings inform and underpin climate response, actions and decisions.

The Te Tāruke-ā-Tāwhiri was a substantial consultation document, listing flagship actions and key moves. One of these was to grow and protect Auckland’s urban forest [to enable it] to capture emissions and build resilience – yet throughout this consultation process, the Auckland Council under the direction of the TMA were busy removing all of the exotic trees and shrubs on the Tūpuna Maunga, they were culling the urban forest.

So, on one hand, Auckland Council have declared an emergency and highlighted the need to protect Auckland’s urban forest, but on the other hand under the direction of the TMA, Auckland Council are reducing their urban forest – as an outsider looking in, this seems… odd!

It is my understanding that the TMA wish to restore the vegetation on the mountains back to a pre-European state. When it comes to revegetation the general rule of thumb is that you use what is there to protected the plants that you want to end up with – revegetation is a long game; making a ngahere (forest) takes time.

In forestry, the temporary use or inclusion of a nurse crop is used to aid the growth and development of the trees they wish to grow. In the case of the Auckland mountains, the nurse crop is already there.

In ecology, where a plant (or organism) benefits from their closely associated neighbours, it is called facilitation. Facilitation, when applied to the restoration of degraded, particularly dry or limiting environments, can greatly improve the success of the target species. Not only can nurse crops facilitate the establishment of target tree species but they can reduce soil loss and improve soil fertility.

The easiest way for the TMA to establish native trees on their ancestral mountains and to restore their Tūpuna Maunga to a pre-European like state is to keep the exotic trees. An easy way for Auckland Council to establish a climate-ready and zero-carbon Auckland is to keep the exotic trees; in the long term, these trees are expendable – but currently, they are providing an ecological service.

In nature the forest cycles; nurse-plants facilitate nurse-plants which in turn facilitate the forest and all that is in it. When it comes to establishing ngahere (or re-establishing as the case may be), you need to mimic nature and use what is there to protected the plants you want to keep. By protecting your target plants form the wind and sun they can grow tall and strong – once the target plants are established, you can remove the non-target, non-native plants and let the forest be.

Creating a ngahere takes time, if the TMA wish to establish tall and strong native trees on their ancestral mountains and restore their Tūpuna Maunga to a pre-European like state, then the TMA and the Auckland Council need to reconsider the removal of what is currently there. The exotic trees are expendable but currently, they are also beneficial – facilitation is key in times of change.

• Written for Tree Matters (NZ)