Tree Roots

Here is a link to the USGA about how tree roots affect golf.  http://www.usga.org/course_care/regional_updates/regional_reports/midcontinent/Tree-Roots-Are-Far-More-Extensive-(And-Problematic)-Than-Most-Realize---September-2014/
I have had to replace part of two drains this season due to tree roots clogging up the drain tile.  First one was 15 green now we have same problem on 6 green/bunker drain.  Roots entering drains is just one problem, tree roots compete with turf for the same nutrients and water.  When water is not plentiful trees win out over turf, the turf will start to go dormant.