Reply to comment by Messier et al. on “Present-day expansion of American beech in northeastern hardwood forests: Does soil base status matter?”Appears in Can. J. For. Res. 39: 2273–2282 (2009).
We respond to the comment by Messier et al. (2011. Can. J. For. Res. 41: 649–653) on our recent paper questioning the possible influence of the base status of soils in the present-day expansion of American beech ( Fagus grandifolia Ehrh.) in Quebec (2009. Can. J. For. Res. 39: 2273–2282). From our observations, as well as from a large body of scientific evidence reporting on the high sensitivity of sugar maple ( Acer saccharum Marsh.) to the acid–base status of soils, we hypothesized that soil base cation depletion, caused in part by atmospheric deposition, is among the main factors involved in the present-day expansion of American beech over large areas in Quebec. Clearly, we suggested in our paper that acid deposition might act with other factors to explain the expansion of American beech. In this context, our conclusions are far from any oversimplified explanation, as stated by Messier et al., but rather, they point out a level of complexity above the one currently discussed.