Area: Casino Strip
Category: Break specific stuff
Vehicle type: Either
Goal: Destroy as many trees as you can in 1 minute
Score for Gold: 34

Strategy #1:

The east-west road it starts you on has trees all down the middle. It's easy to pick them off with a helicopter just by flying through them. Getting yourself aimed in exactly the right direction can take lots of time, so just get close enough and compensate with R & L button strafing. Then turn around and do them again, they regenerate once you get far enough away.