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.