Greenlife matters

Urban trees

For students of horticulture and landscape architecture, there is no better way to learn about trees than to be surrounded by them. Unitec Institute of Technology is a fine example of this ethos. Its park like Mt Albert campus, spread across 55 hectares, is home to a priceless collection of trees and shrubs, including many that are historically significant or rare.

Four years ago, recognising the untapped potential of this rich resource, Senior Lecturer in Landscape Architecture Penny Cliffin and her students set about establishing the Unitec Arboretum.

An arboretum is a living collection of plants and trees that can be used for scientific research and education, as well as to conserve and beautify an area.

Over 2000 trees and shrubs are now officially named and catalogued on the Unitec Arboretum website, www.unitec.ac.nz/trees. On campus the most significant trees have been given informative labels for the benefit of students and visiting members of the public.

A self-guided walk and detailed map can be found on the website. “If you don’t know the name of the tree but you know where it is on campus, you can go to the map and find it there,” says Penny. “We felt that labeling the top 100 most interesting or relevant trees would be effective to start with.” The labeling system is the same as that used by London’s Kew Gardens. “Each label has a QR code, so you can use your smart phone to link to the website and find out about the trees as you go,” Penny explains.

The Urban Forest

A key motivation for the Unitec Arboretum project was to make more of the opportunities for teaching and research. Documenting a valuable collection of trees also means it can be more easily managed and maintained. But, as Penny explains, it doesn’t stop there; the potential benefits of the project are far reaching.

Prior to the Arboretum project Penny did her Master’s degree on Auckland’s tree collections. Her department’s research goals extend into the greater Auckland region.

“The Arboretum allows us to work on projects like the regional planning of green infrastructure and environmental resources, as well as the concept of an urban forest,” says Penny. “The next goal is to establish a wider Auckland database, which would help the Auckland Council develop policy around using the urban forest to mitigate the effects of climate change.”

“When trees absorb carbon dioxide, then turn it into carbohydrates in their structure, so it’s no longer in the air, they obviously provide a mitigation effect against greenhouse gases being released into the atmosphere. So the more trees we have, the better.”

“There’s lots of research about how much, and how [climate change] varies across climates, and across forest types. There’s also research on water absorption, soil stabilisation, storm protection and temperature reduction. If they know how many trees they have and can measure the benefits, the council can more effectively plan the future of Auckland’s urban forest.”

Go Gardening thanks Unitec’s Advance magazine for their contribution to this article.