C. A. Froyd. 2005. Fossil stomata reveal early pine presence in Scotland: implications for postglacial colonization analyses. Ecology 86:579–586.

Appendix A. Age–depth models..

AGE-DEPTH MODELS

A variety of age–depth models, utilizing 95% confidence interval determinations (Bennett 1994), were fitted to the calibrated ages for each sequence. Final models were selected based on calculated "goodness-of-fit", the determination of realistic transitions in sedimentation rates, and accuracy within time periods critical for the assessment of Pinus sylvestris dynamics at each site. A "best fit" 4-term polynomial age–depth model was selected for the Loch an Amair sequence (Fig. A1) and a linear interpolation model (Fig. A2) for Dubh-Lochan (Froyd 2002).

FIG. A1. Ages and 95% confidence intervals plotted against sediment depth from a four-term polynomial age–depth model for the sequence at Loch an Amair. Crosses mark the seven dated sediment samples, horizontal cross arms indicating the age measurement standard deviation and the vertical cross arms, the thickness of the dated sample. Numbers placed alongside the curve indicate example sediment accumulation rates (year cm-1) at periodic intervals.

FIG. A2. Ages and 95% confidence intervals plotted against sediment depth from a linear interpolation age–depth model for the sequence at Dubh-Lochan. Crosses mark the six dated sediment samples, horizontal cross arms indicating the age measurement standard deviation and the vertical cross arms, the thickness of the dated sample. Sediment accumulation rates (year cm-1) between sample points are shown in brackets, extrapolated to the top of the sequence.

LITERATURE CITED

Bennett, K. D. 1994. Confidence intervals for age estimates and deposition times in late-Quaternary sediment sequences. The Holocene 4:337–348.

Froyd, C. A. 2002. Holocene pine (Pinus sylvestris L.) forest dynamics in the Scottish Highlands. Dissertation. University of Cambridge, Cambridge, UK.