Multi-sensor modelling of woody vegetation and canopy cover across natural and modified ecosystems

Remote sensing is an essential tool for monitoring the extent and biophysical attributes of vegetation. Multi-sensor approaches, that can reduce the costs of developing high-quality datasets and improve predictive performance, are increasingly common. Despite this trend, the advantages of these data...

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Bibliographic Details
Main Authors: Stephen B. Stewart, Melissa Fedrigo, Shaun R. Levick, Anthony P. O’Grady, Daniel S. Mendham
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:International Journal of Applied Earth Observations and Geoinformation
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Online Access:http://www.sciencedirect.com/science/article/pii/S1569843225002821
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Summary:Remote sensing is an essential tool for monitoring the extent and biophysical attributes of vegetation. Multi-sensor approaches, that can reduce the costs of developing high-quality datasets and improve predictive performance, are increasingly common. Despite this trend, the advantages of these data-fusion techniques are rarely reported beyond statistical performance. We use airborne lidar-derived metrics to develop models of canopy cover (CC, %) and woody vegetation (WV, presence/absence) using dry-season imagery from the Sentinel-1 (S1 C-band, 5.5 cm wavelength, Synthetic Aperture Radar) and Sentinel-2 (S2, multispectral optical) satellite constellations across natural and modified agricultural ecosystems in Tasmania, southeast Australia. Validation statistics at 18,876 sample locations demonstrated strong performance for both CC (R2 = 0.83, RMSE = 0.13) and WV (OA = 0.94, Kappa = 0.87) when using both S1 and S2 variables for prediction. The small improvement in statistical performance provided by SAR variables (typically 1–2 % for CC and WV) understated the benefits of S1 for discriminating woody vegetation and quantifying canopy cover in non-woody ecosystems (e.g., alpine vegetation, heathlands, wetlands, coastal scrub), demonstrating the complementary benefits of multi-sensor prediction. The emergence and growth of natural capital accounting and frameworks such as the Nature Positive Initiative, mean that high-quality, cost-effective spatial datasets will continue to be in demand. Our study demonstrates the potential of non-commercial, publicly accessible remote sensing imagery to improve fine-scale analyses that may otherwise be cost-prohibitive to apply at scale.
ISSN:1569-8432