Out of boredom and being tired of mass-inspecting my trees (and being too lazy to write down the information), I was poking around the client code to see how possible it'd be to implement something like "on inspect tree: display persistent quality text sprite over tree"
I looked up how Amber does the growth stage display and that's pretty straightforward, but immediately hit a wall since it doesn't look like the client really handles the "Inspect" command at all - probably just sends it to the server and prints back whatever the server returns.
One idea I had in lieu of that is if we can parse the system log, and if a line displays the "Quality:" text, then check if the client clicked on a tree within the last X milliseconds or whatever, then presume that tree was just inspected and tag it accordingly.
Beyond that, I'm guessing actually making the tags persist across sessions would be a fairly involved ordeal, I'm not sure if objects have unique IDs that persist across sessions or such, but yeah. Maybe store a list of tags and the tile location of them and/or tree type, and clear the tag if tree type doesn't match or tile doesn't have a tree on it (though of course trees don't exist solely in a single tile - but yeah - getting ahead of myself here)
And thinking in a larger scope, this could probably just be expanded to store anything that reports quality so you can know at a glance what the Q of your kilns, ovens, etc is.