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Conference paper2020Peer reviewed

Estimation of stem density in hemi-boreal forests using airborne low-frequency synthetic aperture radar

Fransson, Johan; Wallerman, Jörgen; Persson, Henrik; Ulander, Lars M.H.


In this study, Synthetic Aperture Radar (SAR) backscatter data from the Swedish airborne CARABAS-II and LORA systems were used to estimate stem density. The analysis were performed at the test site Remingstorp, located in the south of Sweden, consisting mainly of coniferous in hemi-boreal forests. In total, ten 80 m × 80 m forested areas, where all trees were measured in situ, with stem densities in the range of 278-552 stems and stem volumes in the range of 70-550 m 3 ha -1 were analysed. SAR data from CARABAS-II and LORA were acquired in 2006 with nine unique flight headings. Local maxima of the backscatter were used to estimate stem density. The results were compared with in situ data and the accuracy in terms of root mean square error (RMSE) for CARABAS-II and LORA were found to be 81 stems (20.9%) and 82 stems (20.2%), respectively, in the best cases. The accuracy assessment of the stem density were performed after averaging images from each SAR system. This was done in order to suppress noise to a greater extent compared to using single images. The results show a potential to estimate stem density with low-freqency SAR data for the benefit of forest management.


forestry; synthetic aperture radar; backscatter; vegetation; estimation; biomass; density measurement; airborne radar; synthetic aperture radar; Swedish airborne CARABAS-II; stem density; hemi-boreal forests; stem volumes; airborne low-frequency Synthetic Aperture Radar; Synthetic Aperture Radar backscatter data; LORA system; Remingstorp; Sweden; coniferous forest; forested areas; trees; AD 2006; size 80.0 m; CARABAS-II; LORA; SAR; forest management; stem density

Published in

Title: IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium : proceedings : September 26 - October 2, 2020 Virtual Symposium
eISBN: 978-1-7281-6374-1
Publisher: Institute of Electrical and Electronics Engineers


IGARSS 2020 Symposium, Remote Sensing for a Dynamic Earth, Virtual Symposium. 26 Sep - 2 Oct 2020