Putting trees back into the urban jungle

From The Detail, 5:00 am on 13 March 2023

Trees are often an overlooked feature in cities, but they provide many environmental, social and health benefits. The Detail looks at whether more can be done to improve tree cover in our urban areas.  

A photo taken from the middle of a suburban street looking down the road. Cars are parked on either side. There are large trees with big canopies and thick trunks lining the berms outside houses stretching down as far as visible.

Dignan Street in Point Chevalier is full of liquidamber trees. Photo: RNZ / Tom Kitchin

Around the world, cities are trying to boost their tree cover - and here in New Zealand, it's no different.

While trees have been in the news for smashing into houses and damaging powerlines during the recent storms, there are many benefits to having them in our streets, parks and backyards.

Erika Commers, urban forest team leader at Auckland Council, manages half a million trees on streets and in parks in our biggest city.

Just 18 percent of Auckland's urban area is covered in trees - the council wants that to reach 30 percent by 2050.

"Initially when trees were planted in cities around the world, they were often times planted and chosen and managed specifically for amenity value," Commers tells The Detail.

"But with the amount of research that's been conducted over the past few decades about the benefits trees provide to the inhabitants of urban areas...now we're starting to see trees through a different lens, and understand how much more they contribute then just amenity and how important they are for human wellbeing." 

Erika smiles at the camera. She is wearing a khaki short-sleeved shirt. She is standing in front of a large tree on the berm of a residential street.

Erika Commers is the urban forest manager at Auckland Council. Photo: The Detail/Tom Kitchin

Justin Morgenroth, an associate professor in the school of forestry at the University of Canterbury, is an expert on urban trees. 

The benefits of having trees are many and varied.

"Things like temperature regulation, that's obviously very important to those of us who live in cities...The scientific research has found that people who live or play in green environments tend to have improved mental health benefits. There's studies of things like outpatients waiting in hospitals who recover faster if their view is of trees rather than other land cover types." 

However, he calls the disparity in tree cover between rich and poorer neighbourhoods the "number one issue" in New Zealand cities.

"I don't think we should necessarily vilify the 'richer neighbourhoods' - that's actually what we should all be aspiring to, we as a city should basically be trying to make effective management decisions that gets canopy cover in all neighbourhoods up to those values, rather than say let's get the rich, leafy neighbourhoods down to the lower canopy cover."

Justin smiles broadly at the camera. He is wearing a navy and red gingham shirt.

Justin Morgenroth is an associate professor in the school of forestry at the University of Canterbury. Photo: Supplied/Duncan Shaw-Brown

He's calling for not only restoration plantings, but a plan to identify streets that have limited tree cover and start planting landscape trees to make an immediate impact. 

"In those neighbourhoods also, we've probably got to work with schools, community groups, the larger landowners...and get them involved in supporting tree planting campaigns."

This disparity is glaringly obvious in some parts of Auckland - for example, where the more deprived Māngare-Ōtāhuhu ward has eight percent tree cover, whereas the wealthier Albert-Eden and Waitematā wards have nearly 20 percent cover.

Commers says the Auckland Council is trying to engage with those areas.

"A lot of planting certainly needs to happen, but also even more importantly and more effectively is [the] retention of existing trees. Our intentions with our street tree planting programme is to focus more so on the local boards with much lower canopy cover, especially in residential areas. There's a few different programmes and pools of funding that are focusing resources on that." 

Hear more about the benefits of trees in cities in the full podcast episode.

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