Document: DAN-3-68-19

Jack pine in the absence of fire on Great Wass Island, ME: Bog and outcrop populations.

GRENIER, D.J.* and A.M.BARTON

University of Maine at Farmington, Farmington, ME 04938 USA ¹

Abstract:
We investigated the population dynamics of jack pine (Pinus banksiana) on rock outcrops and in bogs at the southeastern margin of its distribution, in mid-coast Maine. Jack pine is typically a fire-dependent species, which is replaced by more shade-tolerant species, such as spruce (Picea spp.), in the absence of fire. Using analyses of age structure and seedling establishment, we assessed whether jack pine is self-perpetuating on Great Wass Island, where there is little evidence of past fire. The stands generally exhibit patterns indicating self-perpetuating populations, although clear pulses of recruitment synchronized among sites are also apparent, especially on outcrop stands. Factors other than fire, such as climatic fluctuations, are most likely to account for these pulses. Compared to outcrops, bogs tend to have relatively young populations with vigorous trees and many seedlings. These results suggest recent invasion of bogs by jack pine, perhaps as a result of bog succession. This is the first documentation of bog populations of this species, although this has been found for similar fire-associated, stress-tolerant pine species.

Keywords: jack pine, Pinus banksiana, bogs, outcrops, fire, age structure

This abstract is being presented at: 10:30 AM in session:
Poster Session #12: Disturbance Ecology.