The effect of fire frequency on local cembra pine populations
2009
Genries, A. | Mercier, L. | Lavoie, M. | Muller, S. D. | Radakovitch, Olivier | Carcaillet, C. | Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
It has been predicted that global climate change will lead to increasing drought in the Alps during the 21st century, as well as an increased. re risk,. res being currently rare in these mountains. Herein we describe. re frequency reconstruction using high-resolution analyses of macroscopic sedimentary charcoal, pollen, and plant macrofossils. Sediments were sampled from a subalpine pond within the dry western French Alps. Results show that the early-Holocene expansion of Pinus cembra (7200 calibrated years BP) occurred in Acer/Alnus incana/Betula woodlands, which were affected by. res with moderate mean. re-free intervals (MFFI 173 +/- 61 yr [mean +/- SE]). Superposed Epoch Analyses show that the abundance of P. cembra macroremains decreased significantly after burning, although they never disappeared entirely. Statistics suggest that. res spread through cembra pine communities; they were not stand-replacing. res but mainly surface fires, probably killing nonreproductive pines. An increase in. re frequency occurred 6740 years ago, when four. res appear to have occurred within 140 years. These. res may have been associated with a regional drought and could have affected the composition of the subalpine forest by depleting the local P. cembra population in the short term. The predicted increase in drought in the future could, therefore, affect the cembra pine ecosystem in the Alps if. re frequency is reduced to intervals of less than 80 years.
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