Accuracy of photo-optical measurement of wood piles

The correct measurement of harvested wood is economically seen one of the most important tasks in the wood supply chain. In the course of the fast digitalization process in forestry, several apps for mobile devices to facilitate measurement of wood piles using photo-optical approaches are now being used by large forest companies. However, detailed analysis on accuracy of these measurements is not yet available.

Therefore, three widespread apps were tested regarding the accuracy of their volume measurement of wood piles. These results were compared to the up to now used traditional manual wood pile measurement. In total, more than 150 piles of wood from different species and assortments, representing ca. 8,000 m³ of stacked wood, were measured manually and photo-optically in Northern Germany.

In dependency of the respective app, the photo-optical volume measurements of the wood piles deviated by -5.72 % to +4.46 % from the manually derived wood pile volumes in average. It was shown, that the quality of the pile (in terms of quality of piling) can influence both the deviation and the total volume of the pile. When looking at the piles’ dimensions, larger wood piles, with more than 60 m³ of stacked wood, showed a smaller deviation compared to piles with smaller volumes.

It was shown, that the manual measurement itself contains an inherent source of error as well: these volumes differed in average by 2,54 % in dependency of whether the measurement was done starting on the right or left side of the wood pile.

Timewise, the results give a first indication for faster wood pile measurement using photo-optical approaches as well. Based on these results, it can be said that photo-optical approaches can offer a meaningful solution for wood pile measurement. It can be an attractive alternative compared to manual measurement of wood piles, especially when marketing large volumes of wood piles of good quality.