Canopy Top, Height and Photosynthetic Pigment Estimation Using Parrot Sequoia Multispectral Imagery and the Unmanned Aerial Vehicle (UAV)

Unmanned Aerial Vehicle (UAV) equipment used in this study: (a) three-dimensional (3D) models of the mounts designed for the Parrot Sequoia multispectral camera; (b) DJI Phantom 4 quadcopter with attached Parrot Sequoia camera; and, (c) planned flight path in the flylitchi.com web tool.

Unmanned Aerial Vehicle (UAV)

An example of tree crown detection (tree peaks visualized by green dots): (a) watersheds surrounding treetops (white line) split nearby trees—the borders are highlighted in red; DSM on the background; (b) the height mask (yellow line) cuts one side of the tree crowns in a place with a high altitude difference (red highlight); (c) the shadow mask (orange line) reduces the dark parts of tree crowns and completes the tree crown borders; multispectral imagery from the Parrot Sequoia sensor on the background (false-colour composition: Green, Red, Red edge); and, (d) final result of tree crown detection.

An example of tree crown detection (tree peaks visualized by green dots): (a) watersheds surrounding treetops (white line) split nearby trees—the borders are highlighted in red; DSM on the background; (b) the height mask (yellow line) cuts one side of the tree crowns in a place with a high altitude difference (red highlight); (c) the shadow mask (orange line) reduces the dark parts of tree crowns and completes the tree crown borders; multispectral imagery from the Parrot Sequoia sensor on the background (false-colour composition: Green, Red, Red edge); and, (d) final result of tree crown detection.

Title Canopy Top, Height and Photosynthetic Pigment Estimation
Using Parrot Sequoia Multispectral Imagery and the Unmanned Aerial Vehicle (UAV)
Short description of the practice UAV multispectral imaging can support forest monitoring, but needle age is critical for accurate estimation of photosynthetic pigments.
Keywords UAV, Parrot Sequoia multispectral camera, photosynthetic pigments, Norway spruce, forest, linear models, ground truth, needle age, crown detection
Organisation in charge of the good practice Czech Geological Survey, Prague, Czech Republic
Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
Implementation level of the practice Level: Regional / Local

Country:  Czech Republic

Region:  Bohemia

City:  Lysina and  Pluhův Bor
Website http://dx.doi.org/10.3390/rs13040705
Detailed information on the practice UAV multispectral imagery (DJI Phantom 4 with Parrot Sequoia) was used to map spruce forests in Western Bohemia. The method achieved up to 94% crown detection and reliable pigment estimation using second-year needles, offering a practical tool for early forest stress monitoring.
Timeframe Data collection August 2018, published 2021, usable for ongoing monitoring.
Approximate cost Not specified; depends on UAV, sensor, processing software.
Results achieved Tree detection success 76–94%, height estimates correlated with field data (R² > 0.9). Pigment estimation usable with second-year needle samples (R² ≈ 0.45–0.52).
Potential for learning or transfer Transferable to other forest monitoring with common UAVs. Requires calibration, crown segmentation, and appropriate ground truth. Constraints: dense young stands reduce accuracy.
Additional material Original article : Canopy Top, Height and Photosynthetic Pigment Estimation Using Parrot Sequoia Multispectral Imagery and the Unmanned Aerial Vehicle (UAV) (2021).
Contact person Name: Veronika Kopackova-Strnadova

Affiliation: Czech Geological Survey

Email: veronika.kopackova@seznam.cz