A synthesis of remote sensing tools to measure and monitor forest structure and carbon storage

The sustainable management of forest and woodland ecosystems requires practical ways of defining ecosystem services and economic values. Measuring and monitoring vegetation structure is crucial in defining these values. Due to its potential capacity to capture forest structure rapidly and cost-effectively across large areas, there is increasing interest in the application of remote sensing to forest measurement and characterisation. This review seeks to document advances in remote sensing technology applicable to characterising the structure of forest within open dry sclerophyll forests, grassy woodlands and grasslands of the Midlands of Tasmania. The focus of the review is on remote sensing that might support mapping measures of biodiversity and estimation of carbon stock and monitoring of carbon stock change (flux). Section 1 provides an introduction to this literature review and lists the objectives of the document. Section 2 provides a brief overview of forest attributes used to estimate or infer biodiversity and carbon stock. This overview includes both international and Australian literature, and focuses on structural variables that are applicable to the remnant woodlands in the Midlands, Tasmania. Section 3 reviews the current literature to identify which of these attributes can be derived using remote sensing. Key sensor types (optical, radar and LiDAR) and platforms (space, air and terrestrial) are reviewed. Section 4 describes contemporary methods and software for converting point cloud data derived from sensors such as airborne LiDAR and aerial photography into forest metrics that can be used to quantify carbon stock and/or biodiversity. This includes a description of how remote sensing technology can be integrated into carbon accounting models such as FullCAM. Finally, section 5 summarises key opportunities for employing established technologies, such as airborne LiDAR, and emerging technologies, such as unmanned aircraft systems (UAS, also referred to as UAVs or drones), to monitor vegetation, including indications of their affordability, scalability and their current and anticipated future availability.