3D Reconstruction of deciduous trees using low-cost UAV - and crane-based photogrammetry for monitoring shoot elongation across entire canopies

Tree growth determines how much CO2 is sequestered from the atmosphere and temporarily stored in woody biomass. At the same time tree growth is affected by increasing temperatures, more frequent drought periods, late frosts and other extreme events associated with climate change. While continuous measurements of radial (secondary) tree growth using dendrometers are well established, monitoring of shoot elongation (primary growth) has largely been neglected because suitable measurement techniques are lacking. As a result, the effects of climate change on primary tree growth remain insufficiently understood. This work aims at reconstructing native deciduous trees in 3D as a basis for measuring and monitoring shoot elongation over entire tree canopies. Here we explored the use of low-cost UAV photogrammetry and of a multi-camera CraneCam system under real-world conditions. Data were collected in two study areas over an entire growing season. We present sensor evaluations, photogrammetric data acquisition and processing strategies. A special focus is placed on the analysis of the resulting photogrammetric 3D point clouds in terms of accuracy, resolution and completeness. Results demonstrate 3D point accuracies of 5-6 mm for entire trees using consumer-grade UAVs weighing less than 250 g and a 3D reconstruction completeness between 92% and 98% depending on the UAV type. The paper introduces a novel 3Dßprinted ground-truth branch to evaluate the capability to reconstructing fine-detail structures such as thin tree shoots. Finally, we discuss operational challenges and initial experiments towards a skeletonization of entire trees based on photogrammetric point clouds.

Keywords

Subject (DDC)

630 - Landwirtschaft, Veterinärmedizin

Project

Event

XXVth ISPRS Congress

Exhibition start date

Exhibition end date

Conference start date

04.07.2026

Conference end date

11.07.2026

Date of the last check

ISBN

ISSN

1682-1750
1682-1777
2194-9034

Language

English

Created during FHNW affiliation

Yes

Strategic action fields FHNW

Publication status

Published

Review

peer-reviewed

Open access category

Gold

License

Citation

Nebiker, S., Tschanz, M., Amport, N., & Baumgarten, F. (2026). 3D Reconstruction of deciduous trees using low-cost UAV - and crane-based photogrammetry for monitoring shoot elongation across entire canopies. In S. Li, D. Lichti, S. Jabari, A. Yilmaz, Wegner. Jan Dirk, & R. Qin (Eds.), Volume XLIX-B2-2026, 2026 | XXV ISPRS Congress 2026 “From Imagery to Understanding”, Commission II: Vol. XLIX-B2-2026 (pp. 1075–1083). Copernicus Publications. https://doi.org/10.5194/isprs-archives-xlix-b2-2026-1075-2026

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