SwingingRoofer:
can anyone tell me few examples wen i should use that punch shot other then wen around trees?
I can't give specific examples but as Alosso has already said it's a useful shot if you're between distances with your wedges.
My wedges hit 100, 75 and 50 yards full. Punch is (I think!) 83, 72 and 41. If I find myself 80 yards from the hole it's easier to play a punch with a fraction less than full power than try to take 20 yards off a full shot. You do need to use more backspin to get them to stop quickly, the ball flight is lower so they roll more on loanding.
Give it a try, you might need a while to get the hang of punches but once you master them it's like having 3 extra wedges in your bag, 4 if you do it with your PW too.
Nearly forgot, it's a useful shot for hacking out of heavy rough too and as you already know, for keeping the ball under trees.