Well, in German it’s actually »Schnaakenmoor«, a waterland-conservation area in the north-west of Hamburg. Fens are mires in which the water accumulates because the area is slightly lower than the surrounding land, so that there is always an excess of water that rises to ground-level. Mires are inhabited by peatforming plants. As the plants die, they form peat which traps CO2 from the air, as the ground itself is separated from the oxygen in the air, the decomposition processes make it climate-neutral. Most mires nowadays have to be conserved so that they actually keep the water, if they don’t, they will transform into woodland with birches being the most common pioneer species (if around). In that process they will lose their CO2 and release it into the atmosphere, adding to climate change. For that reason it seems appropriate to appreciate these areas and raise awareness for their uniqueness.
The gnat-fen here is in the process of transforming back into wetland, so there are quite some trees around that have to be removed by conservationists.