• Schauffer, Molly
  University of Maine Graduate School
  

Pollen data from perennially wet forested hollows in five Picea (spruce) stands on the eastern coast of Maine indicate what Picea has been well-established (Picea pollen >6%) for at least 5000 years at four of the sites (Roque Island, Schoodic Peninsula. and at two locations on lsle au Haut) Picea became dominant in the fifth coastal stand (on Mount Desert Island) only in the last 2000 years. This is in contrast to the more recent development of Picea stands 1000 years ago at two locations in Big Reed Pond Preserve in northern interior Maine. and the regional expansion of Picea 1000 years ago. evident in previously-published inland lake-sediment pollen stratigraphies. Comparison of modem pollen assemblages with estimates of canopy abundance suggests that small-hollow stratigraphies provide a reasonable characterization of forest dominants living within 50 m of the sample site.

The pollen stratigraphies indicate that the seven sampled Picea stands developed along different pathways with different timings. They imply that stands respond individually to changes in climate, with responses influenced by local micro-site conditions.

The cores contained minimal amounts of charred material, suggesting that fires have not been a major disturbance factor in these stands for the last 5000 years or more charred material in late Holocene sections of three of the coastal cores date to periods of local prehistoric human activity, as indicated by archaeological evidence.

All five coastal pollen stratigraphies - but not the two inland stratigraphies - indicate conditions along the coast became cooler and moister sometime between 6000 and 5000 years ago. These mid-Holocene changes in vegetation correspond with the timing of rapid increases in tidal amplitude and diurnal mixing of cold water in the Gulf of Maine, and provide terrestrial evidence that cool, moist conditions developed along the coast as a consequence of the changes in water circulation.

Should current predictions for near-term climate warning come true, Picea could once again be confined to coastal areas (and other cool, moist micro-sites). Accordingly, landscape-scale physiographic considerations are important in planning for the long-term conservation of Picea in Maine.