City Trees is an iPhone app developed by Steven Merel in the category of Education & Reference. This free app allows users to easily identify tree species in their city using city landscaping data and their current location. With data for 23 cities and over 3.5 million trees, City Trees is a comprehensive resource for tree enthusiasts.

By simply walking up to a tree, users can use the app to display its species. The app utilizes location data and city landscaping information to accurately identify the tree species. Currently, City Trees supports cities such as Austin, Berkeley, Cambridge, Denver, London, Los Angeles, Montreal, New York, Oakland, Pasadena, Philadelphia, Portland, Sacramento, San Francisco, San Jose, Santa Monica, Seattle, Toronto, Victoria, Washington, and Waterloo.

For users whose cities are not yet supported, the developer, Steven Merel, encourages them to email him and request the addition of their city. If the necessary data is available, he may be able to include it in future updates of the app.

City Trees is a valuable tool for anyone interested in learning more about the trees in their city. Whether you're a nature enthusiast, a student, or simply curious about the environment around you, City Trees provides a convenient way to identify and explore the diverse tree species in your area.