Selecting shapereplicators

I was wondering if anyone knew of a method by which to have AI locate and walk to individual shapes in a shape replicator? Beyond that, can you detect if a player has clicked on a replicated shape?

I basically have these forests of trees, and I'd like for the player and AI players to lumberjack. Most MMOs seem to use static shapes for the trees they want you to be able to interact with, and then leave the other background trees as some other designation - so I know the problem might not have a straightforward answer.

I can always use that method if need be. I'm just concerned about rendered shape trees having lightmap shadows, versus static shapes having stenciled shadows :/ That could look a bit odd. Has anyone else experimented with gathering/harvesting of trees? Thanks!