In the USA there is a tree hunter site called the Native Tree Society. As an aside the Native Tree Society was first the Eastern Native Tree Society. The acronym for the original was ENTS. If you are a fan of Lord of the Rings you know what Ents are. If not google it. Most of the posts of tree hunters on the NTS site are from the Eastern US, although there are posts from the Western US, just not as many.
I have learned a lot about trees through this site. Like how large the Tulip tree can grow. Tulip trees aren’t native in Minnesota so I am not familiar with them. Maybe I will try and find a couple seedlings and plant down in my woods. The NTS site also has very detailed information on how to measure trees. It got me looking on Amazon for Laser measuring devices, but because of the cost I haven’t purchased one.
I would recommend going to this site. If you go to the bulletin board you can search for more recent posts about tree hunters and what they have found. Another interesting part of the site are back issues of the ENTS Magazine in PDF format. Lots of stuff for a tree geek. Go and check it out.