Fig 1.
An RGB orthomosaic of the study are, Codo in Catalonia (Spain).
Base map source: USGS National Map Viewer.
Fig 2.
A canopy height model (CHM) derived from UAS-derived 3-D point cloud and a digital terrain model (DTM).
(A) UAS-derived 3-D point cloud. (B) Digital terrain model. (C) Canopy height model.
Fig 3.
(A) RGB orthomosaic image with crown surfaces delineated by ITDe. (B) Image classification with NDVI for non-defoliated (in green) surfaces and defoliated / non-vegetation background (in black) with ITDe. (C) Colour-infrared composite using green, red and nir reflectance bands with crown surfaces delineated by ITDe. (D) Unsupervised classification with ExG for isolating shaded pixels (in grey). (E) Manual digitization of tree crowns (MCDe) for validating the results by ITDe. (F) Image classification with NDVI for non-defoliated (in green) surfaces and defoliated / non-vegetation background (in black) with MCDe.
Fig 4.
Tree species identification and pine processionary moth defoliation in pines in the Codo forest site.
(A) Individutal automatic tree delination on the colour-infrared composite orthomosaic using green, red and nir reflectance bands. (B) Individutal automatic tree delination on the RGB orthomosaic. (C) Automatic tree classification in the field as holm oak or non-defoliated, partially defoliated and completely defoliated pine trhough multispectral high-resolution imagery.
Table 1.
Confusion matrix for non-defoliated, partially defoliated and completely defoliated trees measured in the field or classified by using the multispectral imagery with the automatic ITDe.
Table 2.
Confusion matrix for non-defoliated, partially defoliated and completely defoliated trees measured in the field or classified by using the multispectral imagery with the manual onscreen-digitized tree segmentation (MCDe).
Fig 5.
(A) Mean NDVI values and standard error for pines (P) and holm oaks (Q). (B) completely defoliated (CD), partially defoliated (D) and non-defoliated pines (H) and holm oaks (Q) of the 110 randomly selected trees.
Table 3.
Confusion matrix for classification assessment at the pixel level.
Fig 6.
Linear regression model between PPM defoliation measured in the field and through UAS multispectral images in Codo forest site with ITDe (A) and MCDe (B).
Green: non-defoliated trees; orange: partially defoliated; red: completely defoliated.