Treezilla is a mapping project based in Great Britain that challenges citizen scientists to map every tree in Britain. The mapping interface is easy to use and users can easily add their tree listings and even add photos for others to help them identify species. It’s free to use and the website even offers educational material for inquiry based science lessons. Ultimately, a more complete map of Britain’s trees will help scientists how certain species are affected by climate change, disease, and patterns of land use. The website even has built in tools to measure how much CO2 is captured and what total economic benefit is gained from the different types of species for a given area. Every tree added to the mapping system helps, and Treezilla helps make contributing easy. With the focus of the project is to map trees in urban environments – you can even map the trees in your back yard, school, or local park. Go outside, bring a friend, and start mapping trees today! Project email: treezilla@open.ac.uk