Abstract

In the UK woodland covers 10% of the land area, but little of this is in a completely natural state. Those woodlands which resemble original forests are more highly prized in nature conservation terms. For the management of any woodland (whether conservation or production forests) an indication of woodland quality is required. Typically, the definition is based on a combination of vegetation and habitat composition, structure, disturbance and distribution factors. Biodiversity is another common proxy for measuring woodland quality. Thus, there is no one definition of ‘quality’ and this typically alters between management objectives. Currently woodland quality assessments are performed through fieldwork, where forest stand structure, composition, dead wood, regeneration, and ground vegetation are assessed. Such detailed fieldwork is hampered by cost and restricted spatial coverage, and is often neither objective nor repeatable. Airborne remote sensing offers an alternative to fieldwork, providing a means of extrapolating metrics over large areas. The use of remote sensing for forest applications is not a new concept; aerial photography, for example, has been utilised for forest inventory operations for decades. However, recent developments have allowed the application of new sensors and methods, such as hyperspectral and LiDAR. Combining airborne hyperspectral and LiDAR data is expected to offer detailed and complimentary information about the structure and composition of woodlands, and feature extraction should be improved substantially. This project will pioneer the use of a sensor-fusion approach to surveying forests, with the development of habitat condition indicators at a variety of scales from the individual tree to the landscape level. The method developed will assess the relative contribution of these indicators to determine condition, how they vary across sites, and ultimately how sites are affected by management processes. It is hoped that the techniques developed will be transferable to different woodland sites throughout the UK.