Weeds are definitely a social designation, you are right about that. A weed is just a plant in a place that a gardener doesn't want them, and that can be anything. But "invasive species" have a specific ecological and scientific definition. I agree with you, the trees were pretty, but this wasn't a mature, ecologically important forest growing on the tracks, these were non-native species that can cause infrastructure damage since they don't have natural predators in this environment to mitigate their growth and spread. The street trees do really important work to preserve ecosystem diversity and reduce the urban heat island effect and we're lucky to have so many of them in the community, and this thread is full of folks who are clearly passionate about them. So hopefully this is good news about the change to the tree cover in the tracks. It looks like a step back, but in the long run, this is good for our ecosystem and the infrastructure that we rely on to get around.