Decreasing trend and fluctuations in the mean ring density of Norway spruce through the twentieth centuryTony Franceschini, Jean-Daniel Bontemps, Pierre Gelhaye, Daniel Rittie, Jean-Christophe Herve, Jean-Claude Gegout and Jean-Michel LebanAnn. For. Sci., 67 8 (2010) 816DOI: https://doi.org/10.1051/forest/2010055