Auckland trees thin on the ground

From Nine To Noon, 9:40 am on 22 July 2020

As developments expand in South Auckland, the city's dwindling trees mean many areas remains well under minimum standards for canopy cover.

Published by Auckland Council, data analysed by LiDar (Light Detection and Ranging) surveys between the years 2016-2018 found canopy cover - measuring growth above 3m - across the region's 16 central wards had increased by a net 0.5 per cent, or 60ha, to 18.4 per cent.

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Photo: 123RF

However, the Tree Council's Auckland chairperson Sean Freeman tells Kathryn Ryan the data shows a geographical discrepancy between the number of trees in South Auckland compared to the north of the city. Freeman says it reflects the city's class divide.

“It’s very revealing that this information reflects what many of us in Auckland are very well aware of – the socio-economic division that exists between the south and the north and sure, let's hope councils use this particular report for future planning and future investment for the environment that people in South Auckland live in.

“We all know how important the environment is to everything in our lives, least of all our productivity in the economy and our mental and physical health – these are all driven by the environment we live in.”

Māngere-Ōtāhuhu has the least canopy cover overall, with just 8 per cent, and still lost a further 28ha or 6 per cent.

All five board areas listed in the south of the city are under the stated goal of minimal canopy cover of 15 percent, while there was an increase in the northern areas, including Devonport, Mount Albert and Mount Eden. 

Freeman was concerned about the overall disproportionate ratio of new saplings to mature trees, as older trees continue to be removed.

“We welcome the report. It’s taken four years to get to see it… We are concerned about the kinds of trees we are losing in the city, particularly large trees, old trees and their replacement with very young saplings.

“These are plantings we support and encourage but we just need to note that the Million Trees project that the mayor has been very public about in the last two years, I’m sure that every single tree that has been planted and got into the ground has been counted and documented.

“This report, because of the nature of the technology they’ve used, doesn’t give you that type of detail and unfortunately the blanket approach that the LiDar information provides, hides some these worrying trends.”

He says it provides information to those analysing the figures about the height of the canopy across the city in a very average sense.

Continued development is a driver for removal and is something the report focuses on, he but Freeman says it doesn't account for many of the tree removals his organisation is witnessing.

“They highlight that in their initial summary at the beginning of the report. However, a previous report… which used a different form of analysis did look more closely at trying to understand why trees had been removed in the period analysed and contrary what I thought, which was a desire to new buildings and new infrastructure that was driving the removal of trees, apparently that isn’t the case.

“The trees are being removed are then not replaced - visually from what we can see from satellite imagery - by buildings and infrastructure. So, you can only conjecture as to what drives those owners of property to want to remove those trees.

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 “In our experience as an organisation going to planning hearings on a month-by-month basis, very often these reasons make very little sense.”

The Resource Management Act in 2012 took away blanket protections on private land. 

The report fails to break down how much of the tree removals are on private land and public land and how many are cleared to make way for development, he says. However, its data suggests the vast majority of increases were on public land, and losses on private land.

The largest loss by area was in Hibiscus Bays with 125ha, or 5 per cent of canopy compared to 2013. Howick lost 82ha, or 7 per cent. The data did not include the Waitākere Ranges, Waiheke, Aotea/Great Barrier, Rodney and Franklin, all of which had seen substantial development.

Just eleven met the 15 per cent minimum. 

This is well below the 30 per cent long-term goal set out in the Urban Ngahere Strategy by the council last year. 

“That figure tallies pretty well with other cities across the world – Australia, America and Europe."

Freeman says the benefits of have optimum cover cannot be overstated and are multi-faceted.

"Obviously, the desire is the more canopy coverage you have the more you receive in benefits and services.

“The way they assist us with stormwater management, slowing it down. The way that they clean the air, extracting pollution, the fact that they modify humidity and temperature. Those things are not even looking at the ecological benefits, which are massive. And the psychological and physiological benefits to us as human beings, which we know from the evidence across the world, the more trees we have the better and healthier we are.”