The concept of variety adds to the "isolation" issue. I ,for one, prefer a combination of openness and separation on parkland courses. Glen Mills starts out in the wide open then moves into the trees on #5. Bellewood,nortwest of Philly, is predominately open on the front and treed on the back. Beechtree,Scotland Run,and French Creek all have this mixture.
Please forgive me while I share a brief portion of Rolling Green's exceptionally well done Master Plan by Gil Hanse.
"Fortunately for the members of Rolling Green,we have historic evidence(in the series of aerial photographs),which shows that the course was PARTIALLY (caps mine) wooded and MOSTLY(caps mine) open....Rolling Green was blessed with having variety in this component of the course,with wooded holes and open holes."
Excuse my bias, but I find this analysis more compelling than one's personal experience.
Give me the 250 acres of Bethpage Black and I can give you separation by the use of trees;150 acres+/- and it is not a good idea.