Soil carbon, available nutrients, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands
Carole Bastianelli1,2,3,4, Adam A. Ali4,5,6, Julien Beguin2, Yves Bergeron4, Pierre Grondin7, Christelle Hély3,4,6, and David Paré21AgroParisTech, 16 rue Claude Bernard, 75005 Paris, France 2Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC, Canada G1V 4C7 3EPHE, PSL Research University, 4-14 rue Ferrus, 75014 Paris, France 4NSERC/UQAT/UQAM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC, Canada J9X 5E4 5Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France 6Institut des Sciences de l’Évolution de Montpellier (ISEM), Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France 7Ministère des Forêts, de la Faune et des Parcs, Direction de la recherche forestière, 5700 4e Av O, Québec, QC, Canada G1H 6R1
Received: 12 Jan 2017 – Accepted for review: 14 Mar 2017 – Discussion started: 16 Mar 2017
Abstract. At the northernmost extent of the managed forest in Quebec, the boreal forest is currently undergoing an ecological transition between two forest ecosystems. Open lichen woodlands (LW) are spreading southward at the expense of more productive closed-canopy black spruce-moss forests (MF). The objective of this study was to investigate whether soil properties could distinguish MF from LW in the transition zone where both ecosystem types coexist. All the soils studied were typical podzolic soil profiles evolved from glacial till deposits that shared a similar texture of the C layer. However, soil humus and the B layer varied in thickness and chemistry between the two forest ecosystems at the pedon scale. Multivariate analyses of variance were used to evaluate how soil properties could help distinguish the two types at the site scale. MF humus (FH horizons) showed significantly higher concentrations of organic carbon and of the main exchangeable base cations (Ca, Mg) than LW soils, which were nutritionally poorer. The B horizon of LW sites held higher concentrations of total Al and Fe oxides, and particularly greater concentrations of inorganic amorphous Fe oxides than MF mineral soils, while showing a thinner B layer. Overall, our results show that MF store three times more organic carbon in their soils (B + FH horizons, roots apart) than LW. We suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the of vegetation structure (stand density) and composition (ground cover type) and their subsequent consequences on soil environmental parameters (moisture, radiation rate, redox conditions, etc.). Our data underline significant differences in soil biogeochemistry under different forest ecosystems and reveal the importance of interactions in the soil–vegetation–climate system for the determination of soil composition.
Bastianelli, C., Ali, A. A., Beguin, J., Bergeron, Y., Grondin, P., Hély, C., and Paré, D.: Soil carbon, available nutrients, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands, Biogeosciences Discuss., doi:10.5194/bg-2017-9, in review, 2017.