© 2022 IEEE.In recent years, the efficiency of Terrestrial Laser Scanner (TLS) data for dendrometry has been widely tested and it becomes more widely accepted in small and large scale forests due to its millimeter accuracy. Although TLS products provide high accurate measurements, the high costs of field data collection could be a challenge in some forest stand. Unmanned Aerial Vehicle (UAV) imagery could be an alternative for modeling and monitoring of the dendrometric parameters, specifically on sparse forest. For this purpose, the potential of UAV imagery for diameter at breast height (DBH) estimation, one of the key forest tree parameters, is discussed against TLS based DBH measurements in a Stage D(4) low stem density Oak stand, using point cloud data (PCD)-based ellipse fit. No significant difference was seen between the DBH measurements in regards to the stem diameter. However, the UAVbased DBH measurements had a high variance in the ellipse fit process.