Preface: 2007 ForestSAT

The great majority of papers published in this special issue of the International Journal of Remote Sensing are based on presentations at the 2007 ForestSAT conference, Operational tools in forestry using remote sensing techniques, held 5–7 November 2007 in Montpellier, France. The exceptions are the three papers by Manzo-Delgado et al. (2009), Sprintsin et al. (2009), and Tansey et al. (2009) that have been added to complete the issue. The ForestSAT series of conferences originated from the ForestSAFE project, a five-year, European Union, LIFEEnvironment programme that linked partners in Sweden and the United Kingdom to develop and promote remote sensing and internet technology for forestry and environmental protection. The primary goal of the ForestSAT series has been to raise awareness of the potential of new remote sensing technologies for forest inventory and management. The first ForestSAT conference was hosted by the British Forestry Commission in Edinburgh, Scotland, in August 2002; the second conference was hosted by the Swedish Forest Agency in June 2005 in Borås, Sweden; the third conference was held in Montpellier, France, in November 2007; and the fourth conference is tentatively scheduled for 7–10 September 2010 in Luce, Spain. Most papers report European applications or are by European researchers, although applications in North and South America, Asia, and Africa are reported and papers by North American and Asian authors are included. The papers may be assigned to three broad categories based on type of remotely sensed data and application: (1) multi-spectral imagery for forest attribute assessment, (2) multi-spectral imagery for forest change assessment, and (3) laser scanning data for forest volume and canopy assessment. The exception is the paper by Dunford et al. (2009) that uses photography obtained from an unmanned aerial vehicle (UAV) to assess canopy degeneration in a Mediterranean riparian zone. SPOT and Landsat continue to be the multi-spectral data sources of choice, although Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), Multiple-angle Imaging SpectroRadiometer (MISR), and Quickbird applications are reported. In addition, aerial photography, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Wide Field Sensor (AWiFS), and IKONOS data were used to augment or supplement Landsat and SPOT data. Eight papers report use of multi-spectral data to assess forest attributes. McInerney and Nieuwenhuis (2009) compared the RandomForest decision tree and k-nearest neighbour (k-NN) techniques using Landsat and Irish national forest inventory (NFI) data for assessing forest volume and basal area. They concluded that the k-NN technique was slightly superior. Reese et al. (2009) reported one of the first studies to assess the potential of the IRS-P6 sensor AWiFS and found that estimates of stem volume in Swedish boreal forests obtained using regression techniques were comparable to estimates obtained using SPOT HRV data. Shereen et al. (2009) used a hybrid approach combining SPOT data and aerial photography to identify small, fragmented wooded elements in France which, although small in area, are ecologically relevant for sustaining