Just Accepted
This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.
An assessment of the accuracy of satellite-derived woody and grass foliage cover estimates for Australia
Randall Donohue 
, Luigi Renzullo
Abstract
Context. Understanding the functional role of vegetation across landscapes requires the ability to monitor tree and grass foliage cover dynamics. Several satellite-derived products describe total and woody foliage cover across Australia. Few of these are suitable for monitoring changes in woody foliage cover and only one can currently describe sub-seasonal dynamics in both woody and grass cover. Aims. 1) Improve the accuracy of woody and grass foliage cover estimates in Australia’s arid environments, around major disturbances and in perennially green pastures. 2) Gain a detailed understanding of the accuracy of woody and grass foliage cover estimates for Australia. Methods. Satellite-derived greenness data are converted to total foliage cover fraction (0.0 – 1.0), accounting for differences in background soil affects. Total cover is split into component woody and grass cover using a modified persistent-recurrent splitting algorithm. Results are compared to 4214 field measurements of cover. Key results. Accuracy varies between woody and grassland vegetation types, with total, woody and grass foliage cover having low errors (of around 0.08) and near-zero biases across all woody vegetation types. Across grasslands, errors are higher (up to 0.28), and biases are greater (and negative), with both scaling with foliage density. Conclusions. Foliage cover is accurately estimated for forested through to sparsely wooded ecosystems. Foliage cover of pure, dense grasslands are systematically underpredicted. Implications. This is the only Australian cover product that can generate temporally dense woody and grass foliage cover data and is invaluable for monitoring vegetation dynamics – particularly across Australia’s mixed tree-grass landscapes.
BT24060 Accepted 04 February 2025
© CSIRO 2025
