Here are a few from the ODGs:
"Playing down fairways bordered by straight lines of trees is not only unartistic but makes tedious and uninteresting golf. Many green committees ruin one’s handiwork by planting trees like rows of soldiers along the borders of the fairways." - Alister MacKenzie
"Groups of trees are the most effective way of preventing players reaching the green with their second shots after placing their drives in the wrong direction."
"They make an excellent corner for a dogleg."
"Some of the most spectacular shots I have ever seen have been around, over or through narrow gaps in trees." -
Alister MacKenzie