ALOS PALSAR 25-meter Mosaic Step-by-step Manual on Extraction of Forest Cover and Change Detection Analysis : a manual for users

Good knowledge about natural resources is required to aid in quantifying the effects of climate change, natural disasters and changes in land use. In the context of reducing greenhouse gas emissions from deforestation and forest degradation, conservation and enhancement of carbon stocks and sustainable management of forests (REDD+) it is imperative to analyze changes in forest cover and land use over time to better understand the dynamics of gains and losses in forest carbon stocks and to establish baselines against which performance towards REDD+ compared to business as usual can be measured.

The Philippines have established a strategy towards REDD+ which has become integral part of the Philippine Development Plan 2011-2016 and the National Climate Change Action Plan 2011-2028. The Philippine National REDD-Plus Strategy (PRNRPS) foresees the analysis of forest cover and land use changes by remote sensing technologies as a basis to establish a measuring, reporting and verification (MRV) System for REDD+. But in the Philippines, the results of analysis of optical and multi-spectral remote sensing satellite images are constrained and limited due to severe and regular cloud cover. However, this can be resolved by the use of radar remote sensing technology, but of course, with some limitations.

The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ), in collaboration with the Department of Environment and Natural Resources Forest Management Bureau (DENR-FMB), is implementing the project “Climate-relevant Modernization of Forest Policy and Piloting of REDD in the Philippines” with funding from the International Climate Initiative of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU). The Project supports the implementation of the PNRPS with, among others, development of a model MRV system in a REDD+ demonstration site on Leyte Island.

Under this Project, GIZ has entered into a research cooperation with the Japan Aerospace Exploration Agency (JAXA) under the ALOS Kyoto and Carbon Initiative for the purpose of joint activities in developing national MRV systems, particularly in the application of remote sensing and spatial analyses requirements of REDD+ in pilot activities in the Philippines. In line with this, GIZ has elaborated a methodology which would make use of available images from synthetic aperture radar (SAR) systems and enable forest cover mapping and forest change detection. This includes also field monitoring through a complete forest resource assessment (FRA) in Leyte Island, as a means for accuracy assessment of the generated forest cover maps. The satellite-based forest cover maps and change analyses will serve as baselines and assist in monitoring future changes of forest and land use.

The methodology for analysis of radar data has been documented in this manual.