Comparison of wood stack volume determination between manual, photo-optical, iPad-LiDAR and handheld-LiDAR based measurement methods

Abstract

The measurement of roadside wood stacks in the forest still plays an important role in many forestry operations. Traditional manual measuring methods can be laborious, inaccurate and error-prone. Therefore, the issue is whether 2.5D or 3D optical remote sensing measuring methods provide more precise or detailed results and advantages in further data processing. This study examined and partly developed nine different manual, photo-optical, iPad ® -LiDAR and handheld laser scanner-LiDAR-based wood stack measurement methods. Fortyseven wood stacks, ranging from 8.9 to 209.3 m 3 (totalling approximately 2700 m 3 ), were measured and compared using these nine methods. All the methods give volume estimations, and none can be seen to give the real or true wood stack gross volume. Surprisingly, the results varied significantly within and between the individual methods, with up to a 9% mean relative deviation. The relative deviation is strongly dependent on the size of the wood stack. The 3D measurement methods using iPad ® RGB and LiDAR recorded lower timber volumes than the other methods, in contrast to the method based on samples taken with handheld laser scanner-LiDAR, which overestimated the volume. Generally, optical-and laser-based surveying techniques could be more widely applied in measuring wood stacks in the future. However, such automatic wood stack gross volume determination approaches still face some challenges, regarding accuracy in the case of the 2.5D methods and the lack of automatisation in the case of 3D methods. Consequently, further research is required in the near future.

Automatic Detection and Counting of Stacked Eucalypt Timber Using the YOLOv8 Model

“…Volume is often estimated in stacked cubic meters, and the accuracy of these estimates affects various aspects of timber management and utilization [2], including billing and cost estimation. Inaccurate estimations can lead to significant economic consequences [3].…”

“…While statistical comparisons found no significant differences between the evaluated measurement techniques, practical considerations emphasize the potential financial impact of volume discrepancies [15]. Furthermore, LiDAR-based methods are a trend in these times; it is possible that these methods will complement, or even replace, traditional measurement techniques in the future [3,16,17].…”