Woody Regrowth
Integration of synthetic aperture radar and optical data for detecting woody regrowth
Background
This innovative project lead by Dr Anthea Mitchell, in partnership with NSW DPE and The University of Queensland is paving the way to create a process which accurately detects woody regrowth, resulting in a state-wide spatial product for NSW which may be adopted by other States.
Identifying regrowth from remotely sensed data is highly desired, the applications are currently focussed on supporting State Government activities/legislation but the potential may be far broader, extending to land managers and those interested in identifying vegetation change or biomass.
How
Fig. 1
The woody regrowth project involves the integration of both radar and optically sensed data to derive the final product. By using both active (radar) and passive (optical) sensors, Anthea and associates have been able to capture a measure of biomass and identify the areas of increasing woody vegetation cover within NSW.
Fundamental to the success and development of the project has been the extensive pre-processing carried out on the radar data. The comprehensive corrections to the data account for sensor variations and the distortions attributed from factors such as terrain slope and surface moisture (Fig. 1). A model combining the corrected backscatter data and field measurements provided state-wide estimates of basal area. The change in basal area provides a surrogate measure of biomass change arising from regrowth and land clearing activity (Fig. 2).
Fig. 2
Ongoing research is investigating the use of time-series of optical sensor data and derived products including foliage projective cover (FPC) to model trends in woody vegetation cover change. The challenge is to separate out the often subtle and gradual change associated with increasing woody vegetation from noisy backgrounds and areas of non-woody vegetation.
It is anticipated that the final product will complement the existing SLATS data and form part of an integrated system for monitoring woody vegetation cover change across the State.
Products
All derived products are routinely checked and stored on the Department of Planning and Environments' Science Data Compute (SDC) with standard file naming applied.
Acknowledgements
NSW Department of Planning and Environment
The University of Queensland
Horizon Geoscience Consulting
To find out more -> Contact: anthea.mitchell@uq.edu.au
Published paper: Williams, M.L., Mitchell, A.L., Milne, A.K., Danaher, T. and Horn, G. (2022) Addressing critical influences on L-band radar backscatter for improved estimates of basal area and change. Remote Sensing of Environment, 272, 112933.
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