My 2 cents worth to
coonrad. . .
The good part about your wish to do tree work is that your willing to sign-on as a grounds man. Also, you may be able to seek work as a summer helper so you can get a taste of the work and see how the boss runs the operation.
Some things that might help. . .
Have a CDL.
Be mechanically inclined. Trucks, chippers, and your saws will always need service by the end of the day.
Be first aid certified or at the very least CPR & First Responder trained.
Brush up on your Spanish.
Be forewarned: Every shop has at least one jerk. Don’t sweat him, seniority will eventually pave your way.
Unless your Dad owns the company, be prepared to sweat.
Other info. . .
A number of the linemen I work with were in the tree business and came over to doing high voltage work. According to them linework is both easier & safer, (go figure).
There is another side to tree work. . .
If you have a B.S. or better, there is a scientific/research side. That’s a lot different than “production” work.
Best bet: Start looking at places like TreeBuzz and Gypoclimber.
Them boys are the real-deal. As for me... I’m just a hobbyist.
2 cents applied

Good luck on your adventures!
Electrojake