Yeah so you need to use multipolgyon relations (look at the link in the first message I sent) to avoid the overlapping. I did not mean to insult for "effort"; any contribution on OSM takes effort. It should be allocated properly, in my opinion. I personally greatly value quality over quantity. In the scrub that you map, you miss out on so much detail that I think is what makes a lot of Arizona so beautiful. Although the mountains here are predominately scrub, there are forests in canyons, large sections of rock, and desert grasslands. To familiarize yourself with the difference between some of the natural=* tags see my wiki page: https://wiki.openstreetmap.org/wiki/User:BubbaJuice/Heath_vs._Scrub. I would also just check https://wiki.openstreetmap.org/wiki/Key:natural for more general differentiation.

If I'm being completely honest the first time I mapped landcover by Mount Lemmon it was on iD and it was terrible. iD is not built to handle large amounts of data that are present to map in detail. After I had spent several hours gaining experience elsewhere in JOSM, I came back and redid all of the forest I drew.

I think it may be better if you redirected your effort into possibly mapping forest instead of scrub, as it is generally less complex. There is a lot of forest in northern Arizona that needs mapping. Reach out to me if you have any questions.