Latitudinal differences in the influx of microscopic charred particles to lake sediments in Finland

• Published in: The Holocene
• Main Author: Sarmaja-Korjonen, Kaarina
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 1998
• Subjects: Paleontology; Earth-Surface Processes; Ecology; Archeology; Global and Planetary Change; Kuusamo; Northern Finland; Lapland
• Online Access: http://dx.doi.org/10.1191/095968398666296639; http://journals.sagepub.com/doi/pdf/10.1191/095968398666296639

Forest fires produced charcoal throughout the Holocene and charcoal was preserved in lake sediments. This study compares differences in sedimentary charcoal between southern and northern Finland. Yearly influx of the total surface area of the charcoal particles (μm 2 cm -2 yr -1 ) was estimated at different latitudes: two lakes from southern Finland (60° 21'N, 60° 59'N), two from the Kuusamo area (66° 21'N), NE Finland and one lake from NW Finnish Lapland (68° 40'N). The results show that the mean amount of charcoal deposited in southern Finland was about 10 times higher than that from Kuusamo and 100 times higher than that from NW Finnish Lapland. These differences existed for the whole Holocene and were accompanied by changes in temperature and humidity, as well as drastic changes in forest type. It is suggested that the climatically induced difference in forest biomass at different latitudes accounts for the differences in charcoal influx. Since high-resolution charcoal analyses are not available, it is not clear if the fires were also less frequent in the Kuusamo area; however, there is evidence from Lapland of very long intervals between fires.