Climate change is having an effect on a much-underrated asset in our communities - trees.
Scientists are studying the resilience of urban trees and their ability to survive past 2050.
Christchurch, a garden city in all its green grandeur. But look a little closer at its ancient trees as Australian researchers have and the picture-perfect postcard is anything but a picture of health.
"We assessed 378 species and from these 193 are potentially at risk," Western Sydney University research author Manuel Esperon-Rodriguez said.
More than half the city's trees are already showing signs they're suffering from the higher temperatures that are being recorded.
"We don't know how well urban trees are adapting to the cities, if they are coping well, how they are surviving," Rodriguez said.
It's not just in Christchurch - Western Sydney University forensically investigated native trees by the thousands.
Across 164 cities in 78 countries, thousands of native trees were investigated including oaks, elms, poplar, eucalyptus and cherry plums which are all struggling.
Trees act like natural air conditioners but with more intense heat predicted in the coming years there is a greater chance they'll slowly switch off making it even hotter in large cities - like Sydney where it's predicted almost all of its trees will be living beyond their natural tolerance by 2050.
Researchers recommend giving more thought to planting the species that can better cope with the changing conditions.
Auckland Council arborist David Stejskal looks after Auckland's parks and is aware of the growing threat.
"We have noticed that trees have suffered because of the recent heatwaves," Stejskal said.
He also said it's both native and introduced species that have suffered.
"[It's] trees that would typically sustain lack of rain and higher temperatures, they do succumb not on a great volume but native trees such as taraire [which] are super-susceptible to changes in temperature," Stejskal said.
"We are working with the University of Canterbury and Tasmania in making our species choices more resilient."
Surviving city living could soon come down to how well our trees survive first.
