Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2025, V. 22, No. 5, pp. 195-206
Assessment of the consistency of structural and biometric characteristics of Scots pine forests based on field measurements and UAV imagery
A.D. Nikitina
1 , S.V. Knyazeva
1 , E.V. Tikhonova
1 , A.V. Gornov
1 1 Isaev Centre for Forest Ecology and Productivity RAS, Moscow, Russia
Accepted: 16.08.2025
DOI: 10.21046/2070-7401-2025-22-5-195-206
The paper presents the results of a study evaluating the consistency between structural and biometric characteristics of Scots pine forests derived from ground-based measurements and high-resolution UAV-based RGB imagery. The evaluation included: tree stem diameters obtained from field surveys and corresponding crown areas delineated from UAV imagery; mean tree height measured in the field and height derived from digital surface models; and tree count and canopy cover assessed through ground-based methods versus UAV-based orthomosaics, using both visual interpretation and automatic segmentation approaches. A high Spearman’s correlation (rs) was found between ground measurements and visual interpretation: rs = 0.71 for tree count and rs = 0.75 for mean height. Moderate agreement in canopy cover (rs = 0.59) may reflect not so much the limitations of RGB imagery as the uncertainty of subjective visual assessments in the field, meanwhile UAV-derived data may provide a more objective interpretation. The relationship between stem diameter and crown area derived from orthomosaics reached rs = 0.96 in old-growth sparse pine forests. Additionally, the agreement between visual interpretation and automatic crown segmentation using the Mask R-CNN neural network was assessed: rs = 0.93…0.97 for tree count, crown area, and perimeter; rs = 0.73 for canopy cover, with lower consistency explained by the contribution of undetected crowns to total canopy closure. The study highlights the potential of UAV-based RGB data and automatic segmentation techniques to complement traditional field-based approaches in forest monitoring.
Keywords: UAV, RGB imagery, Spearman correlation, Scots pine, crown delineation, automatic segmentation, Mask R-CNN, forest monitoring
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