SPECTRAL DISCRIMINATION AND CLASSIFICATION OF PINUS SP. WITH MULTISPECTRAL UAS IN A NATURALLY REGENERATING AREA
DOI:
https://doi.org/10.5380/biofix.v11i1.105508Abstract
The spread of Pinus beyond planted areas threatens biodiversity in protected areas, and conventional monitoring of these outbreaks is costly and limited in spatial coverage. We hypothesised that the spectral response of Pinus and broadleaf trees differs consistently across the bands of a multispectral sensor onboard an unmanned aerial system (UAS), and that this difference suffices to support automated classification of invasion outbreaks. The aim was to characterise the spectral signature of both groups and to classify the occurrence of Pinus sp. in a naturally regenerating area. The study was carried out over 11.14 ha at the Canguiri Experimental Farm, Pinhais, Paraná, Brazil, using imagery from a DJI Mavic 3M drone. After object-based segmentation, more than 500 samples per band were extracted to describe the digital numbers (DN) of both groups; the NDVI and NDRE indices, texture metrics and visible bands then fed a Random Forest classifier fitted with 1,354 samples across five thematic classes. Broadleaves showed higher DN in the visible range, notably in the green band (141.81 against 123.31), whereas Pinus prevailed in the near infrared (148.95 against 134.95); the red edge showed coincident means. Classification reached an overall accuracy of 92.8%, a Kappa index of 0.892 and an F-score of 0.856 for Pinus sp., which covered 1.187 ha. We conclude that classifier performance rests on the near infrared and visible contrasts, and that the red edge contributes only in normalised form.
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Copyright (c) 2026 Jordan Luis Campos Modesto Pereira, Caio Cesar Moraes Brandelik, Daniel Zambiazzi Miller, Faiman Orlando da Silva, Lénia Francisco Matsinhe, Ana Paula Dalla Corte

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