People, schools and businesses in Oxford are being offered a chance to make the city greener by adopting trees or planting new ones.
They can choose to plant a new tree in one of the parks or to adopt an existing one near their property, which they then water and look after.
People will also be asked to report any damage to their tree.
The initiative is being run by Oxford City Council's park service until February 2011.
Councillor Mark Lygo, board member for sport, play and school liaison, said: "This scheme is a great way of adding trees into your community and neighbourhood.
"Trees can improve the quality of your local community and help to tackle climate change.
"They also attract birds and wildlife and can help with education projects for children."