Analysis of Regeneration Pattern in a Natural Forest of Northern Japan Using Airborne Lidar and Aerial Photogrammetry

The digital aerial photogrammetry technique and airborne Lidar data are used for investigating the forest height changes. By using aerial photographs taken in the past on a scale of 1:20000, a long-term and large-scale investigation was been attained. The investigated area is about 135ha and the time period is 15 years. The precision of digital aerial photogrammetry using the aerial photographs is less than 2m on a road, and less than 5m in a forest area. DCHM (Digital Crown Height Model) is made from DSM (Digital Surface Model) of aerial photographs and DTM (Digital Terrain Model) of airborne Lidar, and divided into three classes (0-5m, 5-10m, 10m-). Changes of the classes were obtained, and transition probability and equilibrium rate of the classes were calculated. The equilibrium rate is similar to the observed rate of the classes. Therefore, the turnover time can be calculated from the mortality rate; and it is calculated to be 136 years. The technique is found to be effective in analyzing the forest height dynamics and the turnover time.