They didn't cut all of them down, just so the swastika didn't show up anymore. At least that is what they did in one case... I don't know if this is the one.

But honestly, I do find it ok that Germany does this. It is a sort of kick in the balls for them. It is not so much the trees are forming a swastika but the fact that they were planted as such in the service and furthering of nazism, by dedicated nazis

Imagine if the KKK managed to do the same with either KKK or some burning cross (black with yellow trees going upwards, this would be possible)... I doubt it would be allowed to stand long, if it was certain that was what it meant. And in this case there can hardly be a doubt as to that.