ditto on the above, I WAS in the same boat as you, just a farmer tree cutter, and now I did read both of the mentioned books, and BOTH are great books, also the 2nd is great for telling you of the knots you will need.
I to am like you BUT may venture into the field of public. I have bought all the necessary things like climbers, a saddle/harness, I like Weaver myself, GET the better ones not the bottom line or you will buy again, meaning a wider back and leg straps, I learned the hard way and started with a linesman belt LOL. The you will need 2 chainsaws, one for climbing, one big one for tree cutting, ONE rappelling rope for ONLY getting back down out of the tree by rappelling, and a few other ropes for tree pulling, a few caribeeners a figure eight for rappelling, thats just a start to do anything, some wedges also like about 6, a couple of pulleys, a prusik line or 2. that should at least get you started.
BUT the how to fell a tree in VERY good as well as the other, and don't forget about 2 sections of 4 foot rope to practice your NEW KNOTS, and KNOTS are a very big thing in this field.... and DITTO the free labor thing, EDUCATION IS PRICELESS, and to work with some that are open for a week or so would be the best thing experience is the best teacher in my mind, you would just have to sign a waiver for injury/suits ect..........