As far as I know, snake mites that are so easily shared in retail reptiles are NOT native mites & not typically found in our native herps...but that doesn't
mean your snake can't pick up something lethal like cryptosporidiosis from native reptiles that may have passed thru your yard. Natives can & do die from it.
While trees may seem "safer" than the ground, don't forget that birds can carry plenty of things too. Also, wild snakes climb trees.
Call me chicken, but if I take my snakes outside, they remain in my hands. Here ticks are prevalent as are spiders & all sorts of wildlife that have parasites.
(I vaguely remember from many years back that a guy's snake died from what was deduced to be a spider bite in his own enclosure. Spiders can kill us, so
certainly that's another possibility?)