Citizen science can be a powerful research tool. It works especially well for studies where the necessary data does not need special training to collect. TreeSnap from The University of Tennessee Knoxville and University of Kentucky is one such project. TreeSnap uses a smartphone app to collect locations of trees. It particularly emphasizes species affected by invasive insects and diseases. Currently, they focus on ash, chestnut, elm, hemlock, and white oak. The goal of the project is to locate healthy enclaves of these species, especially in forests. Then, scientists can study these trees to determine why they have survived. To add a new tree, users take a photograph and answer a few questions. Approximate GPS locations of trees in the TreeSnap database can be viewed on a map. For privacy reasons, precise locations are available only to researchers associated with the TreeSnap project. The TreeSnap app is available for Android and iOS devices.