Cultural landscape development on a west–east gradient in western Norway – potential of the Landscape Reconstruction Algorithm (LRA)

Abstract

Pollen analysis is the main method to obtain information on human impact on the vegetation through time. In this study, pollen records from one large lake, Kalandsvatn (inner coast), and three small lakes, Herøyvatn (outer coast), Fitjar (inner coast) and Herandsvatn (inner fjord) in Hordaland County, western Norway are investigated. The three small sites reflect different vegetation, climate and landscape types, resulting in different cultural landscapes. A recently developed approach, the Landscape Reconstruction Algorithm (LRA), is used to reconstruct regional and local vegetation cover in five hundred year time intervals, on a gradient from the coast to the inner fjord of western Norway. The regional estimates of vegetation cover as well as local differences between the sites are clearly demonstrated. The coast has been more open than the inner region in all time periods, with less than c. 70% tree cover prior to 5700 cal. BP. On a regional scale the tree cover was c. 90% in the same time period. Gradual opening of the regional forest started between 5700 and 5200 cal. BP. Forest disturbances, probably related to agriculture, are found both at the inner coast and in the inner fjord prior to 4200 cal. BP. Marked openings of the forests took place c. 4200 cal. BP at the outer coast, and c. 3700 cal. BP at the inner coast and inner fjord. From this time, heathlands dominated the open landscape at the coast. In the inner fjord region, grasslands in combination with cereal cultivation characterized the landscape. The inner coast area shows mixed vegetation cover with heathlands, grasslands and cultivated fields. Implementation of LRA suggests a stronger west–east vegetation gradient than indicated in the pollen percentage diagrams. The results show the potential of the LRA-approach in archaeological research.