Speaker
Description
The digital transformation of forest inventories needs the validation of consumer-grade sensors over different phenological stages. This study evaluates the seasonal measurement agreement of stand-level basal area (BA) estimates and operational efficiency between the TreeScanner smartphone application and the FJD Trion P1 professional personal laser scanner (PLS). Research was conducted in fifty circular plots (300 m2) in heterogeneous forests (45–170 years) with rugged topography (slopes 8°–42°) in Brașov, Romania. The experimental design followed a five-dimensional logical order: inter-platform BA agreement within seasons, intra-platform BA variability across seasons for both devices, and seasonal stability of acquisition times for each platform independently. Results regarding inter-platform agreement for BA showed that winter (WI) achieved the highest precision (RMSE: 0.092 m2; Bias: -0.058 m2), while in autumn (AU) it reached statistical parity (paired t-test, p=0.0926). Conversely, spring (SP) exhibited the lowest agreement (RMSE: 0.391 m2; Bias: -0.184 m2) due to vegetative noise. Intra-platform analysis revealed that BA estimates derived from TreeScanner varied significantly between seasons (p < 0.05), primarily influenced by the leaf emergence cycle and annual diameter increments. In contrast, the FJD Trion P1 data (p < 0.05), was significantly impacted by seasonal environmental constraints, such as understory regrowth and climatic variables including snow, mud, or rain. In terms of efficiency of operation, the TreeScanner application, which records the time to scan each tree individually, maintained an inter-season stable non-different (p > 0.05) rate of acquisition (16s/tree approx.). Conversely, the FJD Trion P1, which records the total time to scan the plot, was found to vary significantly (p < 0.05), as its performance proved more sensitive to structural obstructions like growing shrubs and seasonal factors such as snow and rain-induced terrain difficult. It is concluded that Smartphone LiDAR technology is a mature technology for rapid forest inventories with professional-grade agreement during the leaf-off period and better temporal stability than the professional standard.
Keywords: Mobile LiDAR, forest inventory, measurement agreement, phenological cycle, operational efficiency, basal area, personal laser scanning.
| Keywords | Mobile-LiDAR1; personal-laser-scanning2; measurement-agreement3; operational-efficiency4 |
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