Pollen and charcoal in lake sediments compared with historically documented forest fires in southern Switzerland since AD 1920

Tinner, Willy; Ammann, Brigitta; Conedera, Marco; Gäggeler, Heinz W.; Sägesser, Beat; Gedye, Sharon; Jones, Richard (1998). Pollen and charcoal in lake sediments compared with historically documented forest fires in southern Switzerland since AD 1920. Holocene, 8(1), pp. 31-42. Sage 10.1191/095968398667205430

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Charcoal in unlaminated sediments dated by 210Pb was analysed by the pollen-slide and thin-section methods. The results were compared with the number and area of forest fires on different spatial scales in the area around Lago di Origlio as listed in the wildfire database of southern Switzerland since AD 1920. The influx of the number of charcoal particles > 75 µm2 in pollen slides correlates well with the number of annual forest fires recorded within a distance of 20-50 km from the coring site. Hence a size-class distinction or an area measurement by image analysis may not be absolutely necessary for the reconstruction of regional fire history. A regression equation was computed and tested against an independent data set. Its use makes it possible to estimate the charcoal area influx (or concentration) from the particle number influx (or concentration). Local fires within a radius of 2 km around the coring site correlate well with the area influx of charcoal particles estimated by the thin-section method measuring the area of charcoal particles larger than 20 000 µm2 or longer than 50 µm. Pollen percentages and influx values suggest that intensive agriculture and Castanea sativa cultivation were reduced 30-40 years ago, followed by an increase of forest area and a development to more natural woodlands. The traditional Castanea sativa cultivation was characterized by a complete use of the biomass produced, so abandonment of chestnut led to an increasing accumulation of dead biomass, thereby raising the fire risk. On the other hand, the pollen record of the regional vegetation does not show any clear response to the increase of fire frequency during the last three decades in this area.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Palaeoecology
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Tinner, Willy; Ammann, Brigitta and Gäggeler, Heinz

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0959-6836

Publisher:

Sage

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

11 Mar 2016 12:28

Last Modified:

20 May 2016 13:03

Publisher DOI:

10.1191/095968398667205430

Uncontrolled Keywords:

Charcoal analysis, forest fires, fire history, pollen analysis, vegetation change, lake sediments, thin sections, pollen slides, Switzerland

BORIS DOI:

10.7892/boris.77675

URI:

https://boris.unibe.ch/id/eprint/77675

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