Ok about to take the plunge have 2 questions

Ok after debating for a couple of years and pressure from the kids we have decided to put in an
AG pool. My issue is that my septc field is directly behind my house, so I will have to locate of the side of my existing deck and build acces down to it. I have 2 questions
1) I will have to remove a couple of trees. 1, crab apple and 1 pine. What is the best method for this?
2) how close can I build to the Septic field.

I will be calling contractors this week for estimates trying to keep it around 8-10K, wife wants round, I'm thinking oval.

Uh, I don't know. But maybe someone else will.