Survival How To: Using a Mirror to Signal For Help 

Thanks for the helpful demo! Would this technique be helpful while in an area with a lot of tall trees? Would a signal be able to effectively reach a person on the ground or even through a window? I'm curious who's attention I could be able to in fact get. Is it easier to signal someone in the air? You do mention being able to signal to a person on the other side of a canyon so I'm thinking in that case there is a large clearing that makes it easier to signal. Thanks again.