Postglacial migration history of lodgepole pine near Yakutat, Alaska

• Published in: Canadian Journal of Botany
• Main Author: Peteet, Dorothy M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1991
• Subjects: Plant Science; Pacific; Yakutat; Alaska
• Online Access: http://dx.doi.org/10.1139/b91-102; http://www.nrcresearchpress.com/doi/pdf/10.1139/b91-102

Pollen stratigraphy from three peat sections near Yakutat, Alaska, suggests that lodgepole pine only recently arrived in southeastern Alaska. In contrast with this palynological interpretation, however, are lodgepole pine (Pinus contorta) macrofossils that are present throughout one entire peat core. 14 C dating by accelerator mass spectrometry confirms the establishment of lodgepole pine in this region of Alaska about 10 000 BP. The surprising disparity between the pollen and macrofossil results has important implications for paleomigration research. These results imply that the use of assigned pollen percentages to indicate the presence of a species within a region may not be valid, particularly where a species is at the edge of its geographic range. Comparison of the timing of the first appearance of lodgepole pine pollen from a dozen sections along the north Pacific coast suggests either a late Wisconsin refugium for this pine in southeastern Alaska or extremely rapid late-glacial coastal migration northwestward following ice retreat. Key words: Alaska, pollen, macrofossils, lodgepole pine, phytogeography.