November 2017: Common beech [Fagus sylvatica] (Rotbuche): After a wet beginning we had a golden October, very sunny, moderately warm with quite cool nights. This told our trees to prepare for the cold season and we observed a beautiful autumn coloring. In mid October these leaves were still green (see gallery2, October 2017), but within 10 days they turned yellow. I heard from other regions (see SIMB autumn 2017 pictures of Marmo and Longueuil) that the turning didn't occur at the traditional date, maybe due to a warmer and more humid autumn than normal. I suppose that the trees continue with their photosynthesis as long as circumstances permit. Day length doesn't seem to be the crucial signal for leaf coloration. Temperature seems to be more important. As we normally get enough rain in autumn I suppose that a lack of water isn't necessary for the turning.
