Lake sonar surveys and the search for sub-fossil wood

Following the successful utilisation of lake preserved sub-fossil woody material to extend living Scots pine chronologies in Scandinavia, ongoing research in the Scottish Highlands aims to build a similar multi-millennial long climatically sensitive pine chronology. This paper details explorative research testing the use of sonar methods to facilitate the search for sub-fossil material in lake environments. Although the method clearly identifies elongate anomalies that are consistent with submerged tree stems in water depths >1.5 m, it does not allow the identification of sub-fossil wood remnants in shallow water (<1.0 m) or heavily vegetated bays. Therefore, for the successful survey of lakes, a combination of traditional and sonar methods must be applied. Ongoing research will now explore the utilisation of these methods to more remote locations where boat access is not possible. (C) 2011 Istituto Italiano di Dendrocronologia. Published by Elsevier GmbH. All rights reserved.