If you used Willesden Green London Underground station this morning you might not have seen the green for the trees: a pop-up forest has grown there overnight.
There are real trees, mosses, ferns and toadstools, but part of very human-focused project all about giving people something to chew on regarding littering – specifically, dropping chewing gum.
Called the Gum Forest, the Chewing Gum Action Group is using a bit of psychology based on research from Wrigley, which found that people's likelihood of dropping gum is influenced by how natural they perceive a space to be. So, by turning an urban area into a forest, gum-chewers might seek out a bin rather than the ground.
"There are many psychological reasons why people litter, for the most part it's simply thoughtless behaviour, an individual's incapacity to understand how such a seemingly small action can lead to unnecessary and needless environmental damage," explains psychologist Emma Kenny.
"Ironically, it is this disregard for our outside surroundings that in return affects our happiness and wellbeing. There is an abundance of research that evidences how our local environment impacts on our state of mind. The cleaner and more well-kept our surroundings, the calmer, more relaxed and in control we feel as people."
The Willesden Green Gum Forest will only be around for a day, but the trees and plants will find new homes in the neighbourhood's community gardens. Here's a video of it growing.