Assessment of forest information derived from the interoperability of radar and optical data

Time-series optical data extending back to the 1970´s presents a unique capability to monitor the changing extent of the world´s forest resources. Coupled with more recent radar imagery, an operational forest monitoring system that provides long-term, continuous forest measurement and exploits the technical advantages of both sensors is a desirable outcome. To realise this goal, robust and repeatable methods of estimating forest stocks at national scale are required. Standardised methods of linking remote sensing data and forest inventory, generating forest information products, and evaluating and reporting mapping accuracy, are essential to alleviating the high uncertainty in forest cover change estimates. This in turn will facilitate more accurate determination of emissions from forest and land cover change, and so contribute to individual countries´ Measurement, Verification and Reporting (MRV) systems and input to UNFCCC REDD agreements. The Group on Earth Observations (GEO) Forest Carbon Tracking (FCT) task was established in 2008 and aims to address concerns over the lack of standardised methods for the processing and generation of forest information products for use in national carbon accounting. Tasmania, Australia was selected as one of seven ´National Demonstrator´ countries to showcase the use of remote sensing data for consistent, wall-to-wall, time-series estimates of forest and land cover change. In this paper, we present the results of time-series forest mapping over Tasmania using data acquired by Landsat and ALOS PALSAR for the years 2007 to 2009.