Honor System. This is just for fun.
Game Starts Black Friday. Ends Christmas morning.
Only 1 person in a group can call the same tree during an outing.
Exception: If it's a TRUE tie than each person who called it can count the tree.
Tree MUST be inside, on top of, or otherwise touching a vehicle.
1 point given per tree called.
If the vehicle contains more than 1 tree - each tree MUST be called to get the point
If a vehicle has more than 5 trees and the # can not be determined the caller can get a maximum of 5 points for the vehicle
You MUST call the tree. If you see a tree you must shout "TREE!"
Do not call false trees. Don't see that kayak in the distance and call it as a tree "just in case". 
Christmas Trees only. No landscaping trees. Artificial Trees in boxed are allowed.
Drivers: Do NOT crash while looking for trees.
You can call antlers, Rudolph noses or wreaths, but they do not count for scoring.