Turns out we missed a bit of news back in November: On the 8th of last month, Grand Duke Jean watched children (and adults) planting trees in Fischbach. The day was Luxembourg's Dag vum Bam or Day of the Tree. Inititiated by the Stëftung Hëllef fir d'Natur, that Grand Duke Henri is the patron of, the Dag vum Bam has been a patronage of Grand Duke Jean since 1997. The children were obviously delighted to greet the Grand Duchy's former head of state.
A video of the day can be found at RTL.