As city populations soar, it might seem like there isn't much room for trees. But ecologists say these climatic powerhouses are an often overlooked solution to the health and environmental issues greater density brings.
Alongside the eco-services urban trees provide, there are also the qualities "that we can't put monetary value on," says Cris Brack, a forest ecologist from the Australian National University and director of the National Arboretum in Canberra.
Those are "biodiversity, aesthetics and our visceral, gut-need to experience nature," Brack told DW, referring to the concept of 'biophilia' — the idea that humans have an innate desire to connect with nature. Mounting evidence shows that people who live in places with more trees experience lower levels of stress and mental illness, even when controlling for socio-economic factors.