When I bowhunt in Connecticut, where the deer are heavily hunted, I have found that the deer almost watch the trees for hunters. I now climb 25ft up and notice that it has helped. More than anything, what really matters is how well you blend in to your surroundings. The more you can hide yourself in a tree with foliage, the less you will stick out and the less the deer will notice you. Alternatively, during the winter time it helps to wear snow camo to blend in better with the bare trees and white sky on cloudy or overcast days. I almost exclusively hunt from treestands, but always make a point to hunt from the ground a few days each season. There's nothing more exciting than taking a whitetail from eye level.