Data presentation
Histograms of the type published to date (Hicks, 1994) are recommended for showing the influx of individual pollen taxa. These histograms should have the individual years for each pollen trap arranged so that the oldest is at the top of the group and the youngest at the bottom. The traps themselves should be arranged so that the highest altitude sites or the most northerly sites are at the top of the diagram (Fig 2). The pollen influx may be shown as either number of pollen mm-2 year-1 or cm-2 year-1 but it should be clearly stated which scale is being used.
Pie charts are a useful means of summarising data (Hicks, 1992a) when the percentage presence of groups of taxa is being considered.