Small Unmanned Aerial Vehicles (UAVs) have created an opportunity to remotely gather very high-resolution geospatial data for a variety of applications. Recently, UAvs have been widely employed in collecting quantitative measures of crop health indicators such as vegetation and ground cover characteristics. An important crop health indicator is the vertical vegetation structure, which can provide information on plant health and yield. High-resolution data such as optical images or LIDAR point cloud collected by UAVs provide vegetation heights that have proven to be reliable and cost-effective when compared to field methods. With optical images, heights are generated from stereo pairs via photogrammetric techniques while heights are directly estimated from laser point clouds. In this article, we show the potential of data collected by UAV platforms in estimating vegetation heights of citrus plants.