The world is talking trees.
It’s Arbour Day on 5 June, the day that our majestic, silent, green, shade-givers and carbon absorbers get their time in the sun.
It’s a day of reflection for Auckland Council Principal Specialist - Urban Ngahere (Forest), Howell Davies, one of the staff members contributing to the creation and delivery of Auckland Council’s Urban Ngahere (Forest) Strategy.
Howell is an urban ngahere specialist in a team of urban foresters, arborists, tree health experts and ecologists who are being celebrated this Arbour Day for the scale of planting they have achieved across the region.
It’s timely also to focus attention on the scale of tree planting the last decade has seen in two waterfront neighbourhoods in particular: Wynyard Quarter and downtown.
These two newly regenerated parts of the city centre are within a square kilometre and yet 1047 tree specimens have been planted (or mature trees moved and re-planted) there, since the re-design work led by the Auckland Council group began.
The Wynyard Quarter area covered by this story is between Fanshawe Street and Jellicoe Street including Silo Park, Karanga Plaza, Jellicoe Plaza. The downtown area includes Quay Street, Te Wānanga and Te Komititanga where Queen Street meets the sea. Read the research on carbon storage of trees in Karanga Plaza, Wynyard Quarter, here. And watch the return of mature pōhutukawa to Quay Street here.
Currently under construction, Te Hā Noa is the next project in Auckland Council’s midtown regeneration programme making a contribution to the city centre’s expanding ngahere.
More than 20 new native trees are scheduled for planting in Victoria Street, from Elliott Street to Kitchener Street, over the next few years.
“Beautiful trees in this busy part of midtown will provide ongoing benefits of shade, support well-being, attract birds, improve air quality and absorb carbon for many generations to come.
“That’s the beauty of trees,” says Howell Davies.
The wider region
Recent weather events were traumatic for Aucklanders. They were also a stark reminder of the important role trees play in our region.
The social, environmental, economic and cultural benefits that urban trees deliver is well-documented, with cities increasingly recognising the financial value of the services they provide. The USDA Forest Service [PDF] estimated that trees in New York City provide US$5.60 in benefits for every US$1 spent on tree planting and care.
“I am really proud of the care, quality of work, and innovation from Auckland Council arborists, urban foresters and our project teams. They are driving a new best practice for Auckland,” says Howell Davies.
“We are planting hundreds, if not thousands, of new mature trees in our public spaces and millions of seedlings in our regional parks and local reserves to increase Auckland’s urban ngahere, capture our emissions, help reduce stormwater runoff, encourage biodiversity and new birdlife in parts of the city which haven’t seen native birds for decades.
“Our vision is that Aucklanders are proud of their urban ngahere, that Auckland has a healthy and diverse network of green infrastructure, that it is flourishing across the region and is celebrated, protected, and cared for by all,” he says.
There are 16 wide-ranging benefits of trees cited in Auckland Council’s Urban Ngahere (Forest) Strategy. Here are five of those benefits, with source material provided as weblinks:
- The cooling effect of trees, as a result of evapo-transpiration, reduces the urban heat island effect and enhances resilience to an increasing number of hot days (>25°C), one of the projected impacts of climate change. In simple terms, it’s a process where a plant cools itself by sweating water vapour through the pores in its leaves, lowering the temperature of the air.
- Trees intercept rainwater and reduce pollutants washed from hard surfaces into the stormwater system and watercourses. Increasing canopy cover will also contribute towards fewer stormwater overflows from our combined sewer/stormwater systems and therefore lower levels of water pollution in our harbours and streams.
- Trees reduce carbon dioxide (CO2) in the atmosphere through sequestering carbon in new growth. One tonne of carbon stored in wood is equivalent to removing 3.67 tonnes of CO2 from the atmosphere.
- Trees improve air quality by removing air pollutants, such as particulate matter, and absorb gases harmful to human health. A 2006 study estimated that Auckland’s urban trees remove 1320 tonnes of particulates, 1230 tonnes of nitrogen dioxide and 1990 tonnes of ozone.
- An increase in canopy cover would intercept an increased volume of rainwater; reducing and slowing urban runoff and placing less pressure on stormwater systems. International studies [PDF] show that trees intercept 15 to 27 per cent of the annual rainfall that falls on their canopy, depending on a tree’s species and architecture.
The cultural significance of Auckland’s urban ngahere is an important part of Tāmaki Makaurau / Auckland’s wider heritage.
Remnants of early native forest represent traditional supermarkets (kai o te ngahere), learning centres (wānanga o te ngahere), the medicine cabinet (kapata rongoā), schools (kura o te ngahere) and spiritual domain (wairua o te ngahere).
Later, European settlers planted London plane trees along streets in the 1860s which have now grown to create grand tree-lined avenues in the city centre and the adjoining suburbs of Ponsonby, Freemans Bay and Grey Lynn.
Bishop Selwyn, New Zealand’s first Anglican Bishop, is reported to have brought hundreds of Norfolk Island pine seedlings to Auckland in 1858-60. Many of the mature Norfolk Island pines now in Auckland, such as those at Mission Bay, are likely to have been grown from these seedlings. Source: Wilcox, M. D. 2012. Auckland’s Remarkable Urban Forest, Auckland Botanical Society.