Question
We have a grove of silver maples in our backyard (in Indiana) under which we lay
mulch every year.  We'd like to lay out a patio of pavers or flagstone, but digging
down into the ground is impossible, due to the roots.  Can I create a raised
patio?  I am aware of how to lay beds of tamped gravel and sand, etc.  Will this
work and/or will it damage the trees?  I'm thinking of establishing a stable edge
using railroad ties anchored with rebar.  Any thought?  Thanks!

Answer
Of all of the trees, the Silver Maple is probably most resilient to a loosely laid paver patio, as its roots are very shallow and plentiful.  Don't be surprised if this deck "heaves" up after a few years as the roots again continue to seek the surface.  However, I would not ring the tree 360 degrees around the trunk, as this may just be too damaging to a well-extablished tree.

Good idea to "edge" the deck with some sort of restraining device...RR ties are a good choice.

Might I also suggest a free-standing raised deck (wood, or Trex)?  It doesn't have to be elevated very much over the roots: 6-8 inches or so - one step up, or even flush on one edge, if you you have a slight grade difference.  

If it were not a Silver maple, this is what I would suggest as an arternative patio material.  ~M