Let’s take the tūī’s lead on how we regard trees

The pro- and anti-exotic tree debate arising from a delightful NZ Herald photo of a tūī gorging on flowering cherry blossoms raises important questions around an increasingly ideological approach to this country’s plants and animals. It appears ecology is being idealised into a simplistic equation of native equals good and exotic equals bad. This is despite most of our food crops being of non-native origin.

While campaigns to eradicate introduced tree species may appear worthy, they are based on a flawed logic that may ultimately cause more harm than good.

Examples of the misguided commitment to the native tree good / exotic bad construct has seen Tree Council, Forest & Bird and Greenpeace championing Tūpuna Maunga Authority’s plans to destroy 2500 exotic trees on Auckland’s volcanic cones.

Other high-profile examples include Trees That Count (“we love trees but only Aotearoa’s native ones”) and Conservation Minister Eugenie Sage’s Private Member’s Bill to strengthen tree protection – but only for native trees.

This reflects a worldwide trend towards ‘nativism’ in conservation that has made environmentalists biased against introduced species. It has been suggested this trend is underpinned by a manifestation of colonial guilt around how indigenous peoples have been poorly treated the world over. There is a sense that championing native species and advocating the destruction of introduced ones somehow makes amends for the travesties committed.

This approach ironically runs counter to reverence for the Earth mother and all the lifeforms she supports that traditionally lie at the very heart of many indigenous cultures, including Māori.

The NZ Herald photo that sparked furious debate.

There is no question of the need to protect and increase Aotearoa / New Zealand’s native biodiversity, especially in larger native-only forests such as the Waitakere Ranges. However, an ideologically driven approach is scientifically questionable and environmentally damaging in heavily compromised urban areas such as Auckland, which is losing trees – particularly tall ones – at a sickening rate. This could be harmful to human health, recreation and general wellbeing.

Even protected trees are not safe, with Auckland Council and Panuku recently favouring developers over the environment and local communities by approving the removal of a protected macrocarpa tree on public land in Avondale.

Trying to revert this country to fully native vegetation, while an admirable concept, is not only impossible but begs the question of what it would take. DoC has only sufficient funding to control animal pests in a minority of its estate. Getting rid of all animal and plant pests (not to mention exotic plants that are not classified pests) will cost many billions – money that will need to come from other budgets such as health and education.

The same goes for Auckland Council and the millions it votes Tūpuna Maunga Authority.  We have seen figures that suggest it will cost ratepayers more than $1.1 million to destroy all of Ōwairaka’s 345 non-native trees alone.

And that’s just the beginning. Planting plans show the Authority intends to plant native species in very limited areas on Auckland’s maunga. Kikuyu and other non-native weeds will quickly grow into the empty spaces left by the felled exotics, creating increased fire risk, requiring costly maintenance and making a mockery of the ideal to return the maunga to fully native vegetation. Achieving the Authority’s planned rapid conversion to native-only vegetation will require more carbon-emitting mowing and increased herbicide use.

There is also a wider question around what exactly constitutes a “native” species.

When most people think of native, they think of a time before the British colonisation of Aotearoa / New Zealand about 250 years ago. The division between native and exotic is artificially determined by a date, with those showing up afterward deemed alien and therefore unworthy.

In his book Ghosts of Gondwana: The History of Life in New Zealand George Gibbs says: "The original, foundation members of our flora and fauna have undergone profound evolutionary changes, extinctions and invasions throughout their history." He then goes on to discuss fossil records showing large areas of eucalyptus forest in this country up until the Ice Ages, and notes that pūkeko are genetically indistinguishable from the Australian swamphen. The earliest pūkeko remains date to only 400 to 600 years ago; some experts think it is only 300 years since they colonised this country.

Does it therefore make sense to classify eucalyptus as a ‘lesser species’ and plan to mass fell them on Ōwairaka / Mt Albert? And why are pūkeko regarded as more indigenous to New Zealand than sparrows, which arrived maybe 150 years later?

And does it make sense to classify as ‘exotic’ and therefore unworthy trees such as eucalyptus, macrocarpas, olives and flowering cherries that are sacred to indigenous peoples in other parts of the world?

A long-lost environment can never be re-created because nature is constantly changing. Plants and animals have been on the move and adapting since time immemorial – something that can occur more rapidly in today’s urban environments.

Instead of focusing on differences and artificial delineations, why not embrace the interconnections between everything – plant, animal (including human) and microbial – and remember we are all inherently bound to - and by - Mother Earth.

So, let’s follow the tūī’s lead and stop thinking in terms of exotic or native and celebrate those beautiful flowering cherries as the glorious trees that they are. Trees that provide much needed food, homes and shelter for birds and other lifeforms. And trees that provide oxygen for all of us and are a joy to behold.