Effect of the difference of shooting altitude and DTM products on forest measurement by UAV-­SfM

Abstract

Hiroyuki Kobayashi: Effect of the difference of shooting altitude and DTM products on forest measurement by UAV­SfM. Jpn. J. For. Plann. 53: 69~79, 2020 To establish forest measurement method by UAV­SfM, aerial photographs were taken over a Sugi (Japanese cedar) stand with a generalpurpose UAV, combining three shooting altitude (80, 100, 120 m) and three DTM (0.5, 5, 10 m mesh) products. Tree top points were decided, tree heights and canopy area were measured and DBH and volume were estimated using SfM and GIS software. The most precise estimation was obtained by the combination of 100 m shooting altitude and 0.5 m mesh DTM product, and number of trees was 86 (ground measurement was 92),average height was 25.29 m (24.81 m) and plot volume was 104.5 m³ (107.6 m³).