While trying to recreate the arcade stages accurately, while still incorporating the barriers, houses and the tower, I got 19 - 42 trees per stage and only sacrificed anywhere from 1 - 6 trees per stage compared to the arcade.
To put it into perspective, the Intellivision demo that Papa Pete played has 12 trees per stages without barriers, house or the tower.
kells.bmp cannemara.bmp
cork.bmp limerick.bmp
munster.bmp dingle.bmp
tralee.bmp donegal.bmp