Journal
HOLOCENE
Volume 15, Issue 2, Pages 293-297Publisher
ARNOLD, HODDER HEADLINE PLC
DOI: 10.1191/0959683605hl808rr
Keywords
charcoal analysis; palaeoecology; random sampling; sample size; error estimation
Ask authors/readers for more resources
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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available