Trial for recording giant trees with UAV images taken in multiple directions

抄録

The old-growth and giant tree is a nonrenewable resource with great value. It is important to check and record their periodic growth conditions. The purpose of this study was to record the entire tree using aerial images taken by UAV from multiple directions. Since our previous studies showed that UAVs could measure tree height and its DBH with relatively high accuracy, we now focus on the measurement of tree crowns. As a trial, Larix kaempferi located in Mie University Forest was analyzed. Orthophoto and 3D model of the tree were generated by SfM technology, and crown size was measured. As a result, the crown length of Larix kaempferi in the 3D model was 17.2m. UAVs could be useful in recording the information of the entire tree. In addition, as some old-growth and giant trees are at risk of falling due to aging and external pressures such as typhoons, recording the tree crown might help manage old-growth and giant trees.