It takes all kinds of trees to make a forest. Using historic maps and forestry data to inform airborne laser scanning based archaeological prospection in woodland

Abstract

AbstractWhile airborne laser scanning (ALS) data is a key resource for studying afforested landscapes, other datasets are essential to understanding the character of surveyed areas, and for assessing the reliability of the remote sensed data interpretation. This article presents results of such assessment based on the analysis of contemporary forestry data and historic maps for a study area located south of Polanów, Poland, which was subject of bespoke ALS survey. Forestry data and historic maps were initially used to plan ALS data collection, and thereafter to assess data quality and bias. As a result, the longevity and patterning of afforestation were determined and these correlate with the outputs of interpretative mapping together offering a benchmark methodology for identifying survival zones for prehistoric and early medieval earthworks beyond the extents of early and late modern cultivation. In addition, the data characteristics discussed in this article demonstrate the importance of data analysis and survey methodology to inform the understanding of potential bias in the outputs of ALS surveys of afforested landscapes. By understanding this phenomenon at a local scale, the reliability of the data can be estimated. Given the nationwide availability of forestry data across Europe, as well as extensive coverage of historic maps, the results discussed in this article have a general application. Focusing on areas with the highest survival potential can lead to immediate discovery of premodern monuments, and hence prevent them from extensive, forestry management related, destruction.