In recent years, Light Detection and Ranging (LiDAR) has become an essential tool for assessing heritage at a landscape scale. The data created provides a point cloud view of the landscape and allows for the forest canopy to be digitally removed, revealing previously unrecorded features. Thetford Forest was considered to have had a relatively benign effect of the features imposed of the landscape by previous land uses, and this was indeed the case as the raw data was refined. In partnership with Norfolk Historic environment Service and the Brecks from Above project, the data was corroborated with aerial photographs to add 187 new records to the Norfolk and Suffolk Historic Environment Records.
Many new features were identified and ground-truthed by professional archaeologists to prioritise their protection and help landowners understand the importance of managing their sites sensitively. The Forestry Commission and Forest Research held a workshop at Santon Downham village hall for BNG projects and landscape professionals. The workshop was led by Peter Crow from Forest Research who gave an introduction to what LiDAR is and explained how to interpret it in woodland situations, which requires particular caution. Manipulatable data was made available to all BNG projects under a license agreement and was used by several projects to identify new flint mines and military training sites amongst other things. The data was also made public, with a clickable map providing high quality jpeg images, available on the BNG website.
The project was undertaken with the aim of revealing unknown heritage but has generated significant interest amongst other landscape professionals including a PhD student who wants to use tree height data to understand carbon stage and growth patterns, and the British Trust for Ornithology who want to use the data to analyse whether micro-topography influences nightjar nest site selection.
LIDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variables distances) to the Earth. These light pulses, combined with other data recorded by the airborne system, generate precise, three-dimensional information about the shape of the Earth and its surface characteristics. A LIDAR instrument principally consists of a laser, a scanner, and a specialized GPS receiver. Airplanes and helicopters are the most commonly used platforms for acquiring LIDAR data over broad areas.
This project links to all BNG projects that include an element of landscape interpretation, such as The Brecks from Above; Flint in The Brecks; Brecks’ Warrens and Lodges; Sheep in The Brecks; and Brecks’ Military History.
Richard Brooke, Planning and Environment Manager for the Forestry Commission