Factual approach for tropical forest parameters measurement and monitoring: future option with a focus on synergetic use of airborne and terrestrial LiDAR technologies

ABSTRACT

Forest biomass and carbon are critical for ecological monitoring, and yet poorly modelled in complex ecosystems such as the tropical rainforests. To overcome this challenge incurred due to the complex biophysical properties of tropical forests, Airborne and Terrestrial LiDAR (Light Detection and Ranging) technologies have been used combinedly. Airborne LiDAR data ‘from above’ are largely restricted to analyses of lower canopy layer trees. Its combination with Terrestrial LiDAR allows the assessment of tree crowns under the upper canopy layer, thus opening up new possibilities for a more complete assessment of all the trees in a multi-layer stand. In this study, Airborne LiDAR was used for upper canopy tree measurements while Terrestrial LiDAR was complimented for lower canopy layer trees. The result showed that LiDAR-based tree measurements of DBH and height were highly accurate. We highly improved the accuracy of estimated above-ground biomass (AGB)/carbon from 87% of Terrestrial and 90% of Airborne LiDAR-based estimates to 97% through combining the use of the two technologies. This approach contributes to the development of efficient techniques for forest monitoring systems and bears the potential to extend the modelling options from remote sensing data to understory layer trees.

KEYWORDS:

• Above-ground biomass
• Canopy layers
• Ecological monitoring
• Laser technologies
• Tree crown detection

Acknowledgments

This research was carried out by a collaborative of Faculty of Geo-information Science and Earth Observation (ITC) of the University of Twente, Netherlands; and University of Putra Malaysia (UPM). We would also like to thank the anonymous reviewers for the insightful comments despite the difficult situation due to the global COVID-19 pandemic.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by Nuffic, the Netherlands Fellowship Programmes (NFP), Funds for Higher Education, and International Researches Grant (No. 10.13039/501100009295).