We conducted 3D measurements on seven tree species under 1 m tall using a mobile device (iPhone/iPad) to record the 3D leaf shapes, a crucial parameter for assessing tree health. Measurements were taken at both the individual leaf and canopy scales, generating 3D point clouds. The scanning was performed using the Detail mode of the Scaniverse application software. The 3D point clouds were voxelized into three different sizes, and the relationship between the obtained voxel volumes and leaf area was investigated at both scales. At each scale, the voxel volume showed a significant (P<0.01) positive correlation with leaf area. These results suggest that leaf area can be estimated nondestructively and easily via mobile 3D scanning.

In order to estimate the degree of decay within the stem using sonic tomography and predict strength decline, it is necessary to clarify the relationship between the degree of decay, the decrease of sound velocity, and the decrease of wood strength. In this study, the sound velocity and compression strength were measured using small specimens prepared from ‘Somei-yoshino’ wood decayed by white-rot fungi. As the wood density decreased because of decay, the sound velocity decreased linearly, whereas the compression strength decreased curvilinearly. Compared with the decrease rate of wood density, the decrease rate was smaller for sound velocity but larger for compressive strength. These trends were common in tangential, radial, and longitudinal directions and both in air-dry and green conditions.