In Mad Max: Fury Road, Charlize Theron’s Furiosa strives to return to “the Green Place” – a tree-filled oasis in the otherwise lifeless wasteland that the Earth has become. When Furiosa arrives at the sacred spot, however, she finds only skeletal trunks and sprawling dunes. She screams in anguish.
Trees’ services to this planet range from carbon storage and soil conservation to water cycle regulation. They support natural and human food systems and provide homes for countless species – including us, through building materials. Yet we often treat trees as disposable: as something to be harvested for economic gain or as an inconvenience in the way of human development. Since our species began practicing agriculture around 12,000 years ago, we’ve cleared nearly half of the world’s estimated 5.8 trillion trees, according to a 2015 study published in the journal Nature.
For starters, if trees disappeared overnight, so would much of the planet’s biodiversity. Habitat loss is already the primary driver of extinction worldwide, so the destruction of all remaining forests would be “catastrophic” for plants, animals, fungi and more, says Jayme Prevedello, an ecologist at Rio de Janeiro State University in Brazil. “There would be massive extinctions of all groups of organisms, both locally and globally.”
The wave of extinctions would extend beyond forests, depleting wildlife that depends on single trees and small stands of trees as well. In 2018, Prevedello and his colleagues found, for example, that overall species richness was 50 to 100% higher in areas with scattered trees than in open areas. “Even a single, isolated tree in an open area can act as a biodiversity ‘magnet,’ attracting and providing resources for many animals and plants,” Prevedello says. “Therefore, losing even individual trees can severely impact biodiversity locally.”
A growing body of research also points to the fact that trees and nature are good for our mental wellbeing. New York State’s Department of Environmental Conservation, for example, recommends walking in forests to boost overall health, including for reducing stress, increasing energy levels and improving sleep. Trees also seem to help the body recover: a famous study from 1984 revealed that patients recuperating from surgery experienced shorter hospital stays if they had a green view rather than one of a brick wall. More recent research revealed that spending time around grass and trees reduces symptoms in children with attention deficit hyperactivity disorder, and numerous studies have also documented a positive correlation between green space and kids’ performances in school. Trees may even help to combat crime: one study found that a 10% increase in tree cover was associated with a 12% reduction in crime in Baltimore.