That tree line detail is interesting because a lot of the more credible sightings I've come across seem to happen at that exact boundary - between open sky and dense vegetation. Like whatever it is prefers that threshold area.
What was the approximate size relative to the trees? And did it make any sound at all, even a low hum or interference with local wildlife going quiet?
I had something similar about three years back in Ashton Court. Couldn't get a decent photo because my phone just kept losing focus, which in itself felt odd. Stayed stationary for maybe four minutes then was just gone, no movement I could track.
Would be good to hear more detail from others on here who've had similar. There's definitely a pattern with these hovering objects and wooded areas that doesn't get discussed enough.