Measuring Individual Tree Diameter and Height Using GatorEye High-Density UAV-Lidar in an Integrated Crop-Livestock-Forest System

Author(s):Show less -

Dalla Corte, Ana Paula ^[1] ; Rex, Franciel Eduardo ^[1] ; Alves de Almeida, Danilo Roberti ^[2] ; Sanquetta, Carlos Roberto ^[1] ; Silva, Carlos A. ^{[3, 4]} ; Moura, Marks M. ^[1] ; Wilkinson, Ben ^[4] ; Almeyda Zambrano, Angelica Maria ^[4] ; da Cunha Neto, Ernandes M. ^[1] ; Veras, Hudson F. P. ^[1] ; de Moraes, Anibal ^[1] ; Klauberg, Carine ^[5] ; Mohan, Midhun ^[6] ; Cardil, Adrian ^[7] ; Broadbent, Eben North ^[4]

Affiliation

^[1] Fed Univ Parana UFPR, Dept Forest Engn, BR-80210170 Curitiba, PR - Brazil

^[2] Univ Sao Paulo USP ESALQ, Luiz de Queiroz Coll Agr, Dept Forest Sci, BR-13418900 Piracicaba, SP - Brazil

^[3] Univ Maryland, Dept Geog Sci, College Pk, MD 20740 - USA

^[4] Univ Florida, Sch Forest Resources & Conservat, Spatial Ecol & Conservat Lab, Gainesville, FL 32603 - USA

^[5] Fed Univ Sao Joao Rei UFSJ, BR-35701970 Sete Lagoas, MG - Brazil

^[6] Univ Calif Berkeley, Dept Geog, Berkeley, CA 94709 - USA

^[7] Tecnosylva, Parque Tecnol Leon, Leon 24009 - Spain

• Document type: Journal article
• Source: REMOTE SENSING; v. 12, n. 5 MAR 2020.
• Web of Science Citations: 27

Abstract

Accurate forest parameters are essential for forest inventory. Traditionally, parameters such as diameter at breast height (DBH) and total height are measured in the field by level gauges and hypsometers. However, field inventories are usually based on sample plots, which, despite providing valuable and necessary information, are laborious, expensive, and spatially limited. Most of the work developed for remote measurement of DBH has used terrestrial laser scanning (TLS), which has high density point clouds, being an advantage for the accurate forest inventory. However, TLS still has a spatial limitation to application because it needs to be manually carried to reach the area of interest, requires sometimes challenging field access, and often requires a field team. UAV-borne (unmanned aerial vehicle) lidar has great potential to measure DBH as it provides much higher density point cloud data as compared to aircraft-borne systems. Here, we explore the potential of a UAV-lidar system (GatorEye) to measure individual-tree DBH and total height using an automatic approach in an integrated crop-livestock-forest system with seminal forest plantations of Eucalyptus benthamii. A total of 63 trees were georeferenced and had their DBH and total height measured in the field. In the high-density (>1400 points per meter squared) UAV-lidar point cloud, we applied algorithms (usually used for TLS) for individual tree detection and direct measurement of tree height and DBH. The correlation coefficients (r) between the field-observed and UAV lidar-derived measurements were 0.77 and 0.91 for DBH and total tree height, respectively. The corresponding root mean square errors (RMSE) were 11.3% and 7.9%, respectively. UAV-lidar systems have the potential for measuring relatively broad-scale (thousands of hectares) forest plantations, reducing field effort, and providing an important tool to aid decision making for efficient forest management. We recommend that this potential be explored in other tree plantations and forest environments. (AU)

• FAPESP's process: 18/21338-3 - Monitoring forest landscape restoration from unmanned aerial vehicles using Lidar and hyperspectral remote sensing
• Grantee: Danilo Roberti Alves de Almeida
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/14697-0 - Monitoring the demography and diversity of forests undergoing restoration using a drone-lidar-hyperspectral system
• Grantee: Danilo Roberti Alves de Almeida
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor