Detecting Cultural Remains in Boreal Forests in Sweden Using Airborne Laser Scanning Data of Different Resolutions

ABSTRACT

Airborne laser scanning (ALS) is increasingly being used to detect cultural remains in forest landscapes. Boreal forests are challenging, however, since most ancient land use was carried out without major permanent ground disturbances. If this challenge can be met, there is a large potential for surveys through existing nation-wide laser-scanning programs, although their resolutions tend to be low. In this study, we compare the performance of low-resolution (LR) and high-resolution (HR) ALS data in the Krycklan catchment in northern Sweden, an area where ancient land use was small-scale and diverse. About three times as many cultural remains were detected in the HR data set, but the LR set was satisfactory for distinct structures. We analyze how LR data sets can be enhanced at ground-point classification and terrain-model generation and conclude that ALS data have a large potential for the detection and protection of cultural remains in the boreal forest.

KEYWORDS:

• ALS
• LiDAR
• cultural remains
• archaeological survey
• ancient land use
• forest history
• Sami

Acknowledgements

The study was financed by a generous grant to Gudrun Norstedt from Stiftelsen Mauritz Carlgrens Fond. We thank Benedict Alexander for answering many questions when the project was planned and for sharing his unpublished study. We also thank William Lidberg for facilitating access to the Krycklan data, which is funded by Formas. Martin Isenburg kindly granted free and unlimited access to the LAStools software during three months, and Sveaskog and Holmen Skog provided their databases on known cultural remains. The expert consultancy in the field of archaeologists Berit Andersson and Erik Sandén of the Västerbotten Museum was much appreciated. We are also grateful to the editor and two anonymous reviewers for constructive comments on the article.

Disclosure Statement

No financial interest or benefit has arisen from the direct applications of our research.

Notes on Contributors

Gudrun Norstedt (Ph.D. 2018, Swedish University of Agricultural Sciences, SLU) is a consultant at Skogsfrun Natur och Kultur. She is a biologist with a special interest in boreal forest history.

Anna-Lena Axelsson (Ph.D. 2001, Swedish University of Agricultural Sciences, SLU) is a researcher at the Department of Forest Resource Management at SLU. She is also coordinating the SLU forest monitoring program and is responsible for developing a research infrastructure related to the Swedish National Forest Inventory. She has a special interest in open data policy development and data-driven innovation within the forest sector.

Hjalmar Laudon (Ph.D. 2000, Swedish University of Agricultural Sciences, SLU) is a professor at the Department of Forest Ecology and Management at SLU. He is the scientific director of the Krycklan Catchment Study (www.slu.se/Krycklan). His research interest is primarily directed towards how water quality is influenced by land use and climate on a landscape level.

Lars Östlund (Ph.D. 1994, Swedish University of Agricultural Sciences, SLU) is a professor at the Department of Forest Ecology and Management at SLU. His work focuses on the forest history of northern Scandinavia and to some extent western North America and Patagonia in Chile. He has a special interest in indigenous forest use and how the legacy of such use is protected today and also the relationship between natural and cultural values in old-growth forests.

ORCID

Gudrun Norstedt http://orcid.org/0000-0002-4438-3547