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Abies lasiocarpa is a major element of high elevation forests and parkland of British Columbia, Canada, and adjacent regions, yet its history, especially in the late-glacial, is poorly understood. We present four new pollen and macrofossil records, summarize modern surface spectra and review previous studies to understand the role of A. lasiocarpa during the marked climatic changes of the late-glacial and early-Holocene. Today, in southern British Columbia, A. lasiocarpa reaches between 5 and 20% cover in the vegetation at Crater Lake, Buckbean Bog, and Lake of the Woods, but the 1–5% Abies pollen values under-represent its occurrence in the vegetation. At Sicamous Creek Lake, A. lasiocarpa grows at 50% cover and Pinus is absent locally, but the modern pollen surface spectra under-represent sub-alpine fir at 10% of the pollen rain. Based on these observations, sediments from Sicamous Creek Lake, Crater Lake, Buckbean Bog, and Lake of the Woods reveal that Abies grew locally in the late-glacial period. On southern Vancouver Island, British Columbia, the occurrence of an A. lasiocarpa needle, dated to 11 900±400 14 C yr BP in a lake core, along with only 1–2% Abies pollen, suggests that the tree grew at low elevations where it does not today. These results and a review of regional paleobotanical records suggest that the role of A. lasiocarpa in late-glacial and early-Holocene vegetation communities has been under-estimated. This species was likely a major element of the vegetation during this interval and among the first tree species to colonize deglaciated surfaces. Considering the magnitude of future climate change, a better understanding of the history of A. lasiocarpa during previous climate changes is necessary to project vegetation response and design effective resource management plans. |
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