UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches

The use of unmanned aerial vehicles (UAVs), particularly with high-density point clouds obtained through UAV laser scanning (ULS) and UAV structure from motion (UAV-SfM) techniques, offer cost-effective alternatives for forest inventory. However, the literature lacks comprehensive assessments of the...

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Main Authors: Robin J.L. Hartley, Sadeepa Jayathunga, Joane S. Elleouet, Benjamin S.C. Steer, Michael S. Watt
Format: Article
Language:English
Published: Elsevier 2025-12-01
Series:Science of Remote Sensing
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666017225000513
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author Robin J.L. Hartley
Sadeepa Jayathunga
Joane S. Elleouet
Benjamin S.C. Steer
Michael S. Watt
author_facet Robin J.L. Hartley
Sadeepa Jayathunga
Joane S. Elleouet
Benjamin S.C. Steer
Michael S. Watt
author_sort Robin J.L. Hartley
collection DOAJ
description The use of unmanned aerial vehicles (UAVs), particularly with high-density point clouds obtained through UAV laser scanning (ULS) and UAV structure from motion (UAV-SfM) techniques, offer cost-effective alternatives for forest inventory. However, the literature lacks comprehensive assessments of their limitations across diverse ranges of age classes and site conditions. This study addressed this gap by evaluating the estimation accuracy of crucial tree attributes, diameter at breast height (DBH) and tree height, in a range of age classes within forest plantations. In addition, this study thoroughly evaluated the performance of ULS and UAV-SfM in diverse site conditions using point clouds obtained from Pinus radiata D. Don plantations, a widely planted commercial timber species worldwide. To achieve this, UAV and field data were gathered from twelve sites, including multitemporal data for four sites. By employing an automated data processing pipeline, individual trees were segmented and structural metrics extracted from tree segments to estimate DBH and tree height at an individual tree level. Results indicated that UAV-SfM and ULS performed comparably in estimating DBH over the entire dataset, with R2 values of 0.67 and 0.74 and RMSE values of 2.05 cm (11 %) and 2.13 cm (11 %) respectively. However, ULS generally outperformed UAV-SfM at the site level, achieving higher R2 values (0.46–0.90 vs 0.21–0.85) and RMSE values (0.33–7.24 cm at 7–24 % vs. 0.35–6.15 cm at 8–17 %). ULS also consistently outperformed UAV-SfM in tree height measurements across sites, with an average per site RMSE of 0.68 m (5.4 %) compared with 1.21 m (11.59 %), demonstrating its robustness in diverse conditions. Site-specific factors such as stand maturity and logging debris affected measurement reliability in both datasets, with accuracy improving for younger sites, sites with a more open canopy and more favourable site conditions (less logging debris and weed cover). The study also indicated a moderate relationship between ground sampling distance (GSD) of the imagery and UAV-SfM accuracy. The findings highlight the significance of considering site-specific variables when choosing UAV technologies for conducting forest inventory, ensuring informed decisions in UAV-based forest inventory practices. Consequently, the insights gained from this research hold significant importance for practical forestry applications.
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spelling doaj-art-e90e3b3e0e854527a87c26af91b49e362025-08-20T03:15:03ZengElsevierScience of Remote Sensing2666-01722025-12-011210024510.1016/j.srs.2025.100245UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approachesRobin J.L. Hartley0Sadeepa Jayathunga1Joane S. Elleouet2Benjamin S.C. Steer3Michael S. Watt4Scion, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New Zealand; Corresponding author.Scion, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New ZealandScion, Level 6, 17-21 Whitmore Street, Wellington Central 6011, New ZealandScion, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New ZealandScion, 10 Kyle St, Christchurch, 8011, New ZealandThe use of unmanned aerial vehicles (UAVs), particularly with high-density point clouds obtained through UAV laser scanning (ULS) and UAV structure from motion (UAV-SfM) techniques, offer cost-effective alternatives for forest inventory. However, the literature lacks comprehensive assessments of their limitations across diverse ranges of age classes and site conditions. This study addressed this gap by evaluating the estimation accuracy of crucial tree attributes, diameter at breast height (DBH) and tree height, in a range of age classes within forest plantations. In addition, this study thoroughly evaluated the performance of ULS and UAV-SfM in diverse site conditions using point clouds obtained from Pinus radiata D. Don plantations, a widely planted commercial timber species worldwide. To achieve this, UAV and field data were gathered from twelve sites, including multitemporal data for four sites. By employing an automated data processing pipeline, individual trees were segmented and structural metrics extracted from tree segments to estimate DBH and tree height at an individual tree level. Results indicated that UAV-SfM and ULS performed comparably in estimating DBH over the entire dataset, with R2 values of 0.67 and 0.74 and RMSE values of 2.05 cm (11 %) and 2.13 cm (11 %) respectively. However, ULS generally outperformed UAV-SfM at the site level, achieving higher R2 values (0.46–0.90 vs 0.21–0.85) and RMSE values (0.33–7.24 cm at 7–24 % vs. 0.35–6.15 cm at 8–17 %). ULS also consistently outperformed UAV-SfM in tree height measurements across sites, with an average per site RMSE of 0.68 m (5.4 %) compared with 1.21 m (11.59 %), demonstrating its robustness in diverse conditions. Site-specific factors such as stand maturity and logging debris affected measurement reliability in both datasets, with accuracy improving for younger sites, sites with a more open canopy and more favourable site conditions (less logging debris and weed cover). The study also indicated a moderate relationship between ground sampling distance (GSD) of the imagery and UAV-SfM accuracy. The findings highlight the significance of considering site-specific variables when choosing UAV technologies for conducting forest inventory, ensuring informed decisions in UAV-based forest inventory practices. Consequently, the insights gained from this research hold significant importance for practical forestry applications.http://www.sciencedirect.com/science/article/pii/S2666017225000513DBHTree heightLidarSfMRadiata pineRandom forests
spellingShingle Robin J.L. Hartley
Sadeepa Jayathunga
Joane S. Elleouet
Benjamin S.C. Steer
Michael S. Watt
UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
Science of Remote Sensing
DBH
Tree height
Lidar
SfM
Radiata pine
Random forests
title UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
title_full UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
title_fullStr UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
title_full_unstemmed UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
title_short UAV-enabled evaluation of forestry plantations: A comprehensive assessment of laser scanning and photogrammetric approaches
title_sort uav enabled evaluation of forestry plantations a comprehensive assessment of laser scanning and photogrammetric approaches
topic DBH
Tree height
Lidar
SfM
Radiata pine
Random forests
url http://www.sciencedirect.com/science/article/pii/S2666017225000513
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AT joaneselleouet uavenabledevaluationofforestryplantationsacomprehensiveassessmentoflaserscanningandphotogrammetricapproaches
AT benjaminscsteer uavenabledevaluationofforestryplantationsacomprehensiveassessmentoflaserscanningandphotogrammetricapproaches
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