By Mark Kinver, BBC
A project aims to plant three million trees - one for every man, woman and child - in Greater Manchester over the next 25 years.
Those behind City of Trees hopes the effort will not only green the region but improve our understanding of the benefits trees provide to society.
These include reducing stress, improve air quality and the amount of time shoppers spend in retail areas.
The project is also testing how trees can reduce flooding in built-up areas.
City of Trees director Tony Hothersall explained that the scheme had three main objectives.
"One is to plant three million trees, ie. a tree for every man woman and child, over the next 25 years," he said.
"Next, we are very much focused on bringing existing woodland into management because there is no point in planting new woodland if you can't manage what you've got already.
"Finally, we want to engage people a lot more in their natural environment; in planting trees; in managing areas; in understanding more about the benefits that trees and woodlands bring to our society."
