Accurate measurements in forest inventories are crucial. Though manual measurements are precise, they are time consuming, while most of the times, the amount of collected data is limited in Diameter at Breast Height (DBH) and Height. Contemporary technological achievements such as Terrestrial Laser Scanner (TLS) and Unmanned Air Vehicle (UAV) can be used in forest inventories, where capturing detailed and highly accurate information, such as geometry, texture or color, can be obtained in great detail and speed. This study is focusing on semi-automatic tree and tree crown parameters extraction from Point Clouds (PCs) acquired by TLS and UAV, on a plot level. PC derived from TLS procedure and from combination of TLS and UAV were further studied. Tree and crown parameters were computed for both PC datasets, which are tree position, DBH, Stem Curve, tree planar projection, Crown position, Crown bottom height, Crown total height, Crown volume and surface area and Crown intersections. Tree height and DBH parameters of both datasets were further compared with manually derived field data measurements. TLS PC gave satisfying results regarding DBH (Pearson's r: 0.971, R2: 0.9427) while at Height there was a significant loss of information due to obstruction by lower branches (Pearson's r: 0.524, R2: 0.2747). TLS - UAV combined PC has better but not adequate results at Height (Pearson's r: 0.581, R2: 0.3380) where loss of information was also occurred due UAV camera sensor insufficiency in capturing the upper stem.