Denmark - Seaweed Houses and Sea-salt Huts, Laesoe Island

 

Seaweed houses:

1. Museumsgården, Museumsvej 3. N57 15 47 – E11 01 57

2. Hedvigs Hus, Linievejen 36. N57 18 27 – E11 07 32

Sea-salt production cultural landscape:

3. Rønnerne (nature- and sites and monuments-protected areas, approx. defined by the points:) N57 13 33 – E11 00 33, N57 14 16 - E11 03 27 and N57 11 48 E11 07 43 Additional component parts (Seaweed houses) to be confirmed

Laesoe Island (Danish: Læsø) is a small lowland archipelago situated in the northern part of Kattegat, the strait which separates the North Sea and the Baltic Sea between Denmark and Sweden. The property is a serial nomination which demonstrates exceptional ingenuity and creativity from the early Middle Ages to the mid-twentieth century in the exploitation of the marine resources of salt and seaweed (eelgrass, Zostera marina) by a small and relatively isolated island community.

The property broadly comprises a large coastal heath and wetland landscape of medieval sea-salt production in the south of the island, together with two clusters of ‘seaweed’ houses in the east and northeast of the island, and an area of sandflats and sea in the southeast associated with the source of eelgrass used in roofing.

Cultural landscape of large-scale medieval (12th-16th century) sea-salt production

Shallow and patchy concentrations of saline groundwater (2-17%) occurred in superficial postglacial marine sands and gravels resting on impermeable clay beneath coastal sandflats, salt marshes and meadows in the south of Laesoe. Archaeological sites of around 1,700 sea-salt production huts (salt cotes) are recorded in the component part. Such sites typically comprise stone furnaces, embankments and mounds distributed in distinctive landscape patterns that represents successive exploitation near a retreating coastline. This corresponds to successive raised and stranded palaeo-shorelines that indicate the extent and direction of coastal change caused by centuries of natural marine regression related to post-glacial rebound. So many salt cotes, and in unique arrangement, is a rare manifestation of open-pan salt production once common in medieval Europe where, and when, salt was essential for preserving food, notably fish (especially herring from the Baltic and North seas), and in other aspects of life and commerce.