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Recent expansion of jack pine in peatlands of southeastern Québec: A paleoecological study

2003; Taylor & Francis; Volume: 10; Issue: 2 Linguagem: Inglês

10.1080/11956860.2003.11682772

2376-7626

Stéphanie Pellerin, Claude Lavoie,

Botany and Plant Ecology Studies

Jack pine (Pinus banksiana) colonization and expansion in ombrotrophic peatlands of the Bas-Saint-Laurent region, southeastern Québec, was analyzed using macrofossil and dendrochronological analyses. During the last 80 years, and mainly between 1920 and 1945, several open peatlands dominated by Sphagnum species were invaded by jack pine following a fire event. This phenomenon appears to have no precedent over the last 8,900 years, at least in one of the study sites. Fires triggered the expansion by eliminating the Sphagnum mat and spreading thousands of pine seeds released by a few individuals. While fires contributed to the expansion of pines in bogs, this phenomenon may have been facilitated by a drier-than-average climatic period during the first part of the 20th century. The fact that dense jack pine stands are now growing on thick organic deposits indicates that this species has a wider ecological tolerance than previously known and/or that the Bas-Saint-Laurent peatlands have recently undergone major ecological and hydrological changes favouring the growth of non-bog species.