Minimum count sums for charcoalconcentration estimates in pollen slides: accuracy and potential errors

Finsinger, Walter; Tinner, Willy (2005). Minimum count sums for charcoalconcentration estimates in pollen slides: accuracy and potential errors. Holocene, 15(2), pp. 293-297. Sage 10.1191/0959683605hl808rr

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Charcoal particles in pollen slides are often abundant, and thus analysts are faced with the problem of setting the minimum counting sum as small as possible in order to save time. We analysed the reliability of charcoal-concentration estimates based on different counting sums, using simulated low-to high-count samples. Bootstrap simulations indicate that the variability of inferred charcoal concentrations increases progressively with decreasing sums. Below 200 items (i.e., the sum of charcoal particles and exotic marker grains), reconstructed fire incidence is either too high or too low. Statistical comparisons show that the means of bootstrap simulations stabilize after 200 counts. Moreover, a count of 200-300 items is sufficient to produce a charcoal-concentration estimate with less than+5% error if compared with high-count samples of 1000 items for charcoal/marker grain ratios 0.1-0.91. If, however, this ratio is extremely high or low (> 0.91 or < 0.1) and if such samples are frequent, we suggest that marker grains are reduced or added prior to new sample processing.

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

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0959-6836

Publisher:

Sage

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

08 Dec 2015 14:17

Last Modified:

20 May 2016 13:31

Publisher DOI:

10.1191/0959683605hl808rr

Uncontrolled Keywords:

Charcoal analysis, palaeoecology, random sampling, sample size, error estimation

BORIS DOI:

10.7892/boris.73962

URI:

https://boris.unibe.ch/id/eprint/73962

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