2 saplings of Golden Rain Tree i.e. the plants with yellow leaves; cut and poisoned but most likely too late for these deciduous species - the privet was also treated
It isn’t easy for me to tell from the photo but it looks like Koelreuteria paniculata rather than Fraxinus sp. Mature trees of both occur nearby so you could compare leaves. I thought you had simply picked the wrong golden rain tree: Koelreuteria elegans does not occur in this region.