And here is the chart to follow the progress:
https://taginfo.openstreetmap.org/tags/natural=tree#chronology
We should see a saturation arround 3 trillion trees. (1)
You can easily help achivieving this goal by reworking natural=tree_row and adding single natural=tree into natural=wood areas :) I know, some say this is discouraged, but we really need to map EVERY TREE!
The person to the right?
Sometimes I even think about adding a Google Maps Link to POIs, because of Reviews. The reviews helping a lot to know what to expect from a POI before visiting them.
Thankfully there is no established tag yet.
I had the feeling the author is meaning rogue in a positive way here. At least the article sounds quite positive and impressed about that project.
same for hiking and biking routes. I found some obvious errors but I am not able to fix it with ID. I created some notes for them but since several monthes nobody fixed it.
Unfortunately most of the species tagged trees are mass imported and not mapped by a real mapper.
I try often to map species or genus but there is no good mobile app for this task yet.