Pollen and charcoal analyses from Lake Etu-Mustajärvi, Southern Finland, with special reference to an early Holocene Urtica pollen maximum

Abstract

Sediments of a small lake, Etu-Mustajärvi, in southern Finland, were studied with respect to their fossil pollen and charcoal content. Pollen analysis showed a typical development of vegetation from the earliest Holocene onwards, since the isolation of the lake from the Baltic Ice Lake. The emerged land was first colonised by herbs and bushes, and for the first time in Finland an Urtica maximum of 4 % is reported for this period. It is considered possible that Urtica may have been a commoner part of the pollen flora of newly emerged land in south Finland than has been previously thought. Charcoal analysis was undertaken to examine the Holocene history of forest fires in the area. At least in the Lammi area, charcoal seems to have been most abundant about 8000-6000 BP, a result which is in apparent disagreement with the general concept that the period was moist and thus forest fire frequency could not have been high.

Keywords

• paleoecology
• lake sediments
• paleobotany
• pollen analysis
• Urtica
• charcoal
• fires
• Holocene
• Lammi
• Finland