Kim Calders, Associate Professor, Ghent University

Multi-scale lidar for monitoring forests

Abstract: Quantifying forest structure and its temporal dynamics is fundamental for understanding ecosystem processes and their role in the global carbon and water cycles. Conventional field measurements capture only limited aspects of forest structure and can be limited for objective repeat assessments of change. Remote sensing approaches provide broader coverage but often lack consistent connections to in situ data. Multi-scale lidar offers a pathway to bridge these limitations by providing structural information from individual trees to entire regions and by enabling more objective and traceable repeat measurements at relevant temporal resolutions.

Recent advances in terrestrial, drone (UAV), and airborne lidar have expanded the possibilities for monitoring forests across scales. Automated terrestrial lidar now allows near-continuous observation of canopy development, plant/leaf area variation, and structural interactions with, for example, microclimate. UAV- and airborne-based lidar systems extend the coverage to larger areas, producing dense three-dimensional datasets over landscapes that are otherwise difficult to access. These approaches create new opportunities but also pose methodological challenges concerning data fusion, upscaling, and long-term consistency.

In this seminar, case studies from tropical and temperate forests, including work on giant old trees, demonstrate how multi-scale lidar can be used to detect disturbance, quantify recovery trajectories, and constrain models. Ongoing efforts aim to establish permanent monitoring networks and to integrate lidar with other data streams, supporting a new generation of ecosystem observations that explicitly capture forest structure and change.