In today's electronic age, suburban and city children are increasingly disconnected with the natural world. Studying trees allows children to learn about the world they live in and can teach a variety of useful topics contained within the National Curriculum in England. Knowledge of trees is specifically required in the science curriculum at key stage 1 (ages 5-7) under the topic "Plants." Trees are mentioned again at key stage 2 (ages 7-11), in particular in year 3 (ages 7-8) when knowledge of plant or tree structure is required. However, looking at trees can also be used to cover a range of geography, mathematics and citizenship topics. In this article, the author shares his ideas for teaching city children about urban trees, an ideal approach to teaching a range of geography, maths and science topics at primary level, while helping to reconnect the children with the natural world around them.