Quote Originally Posted by Pete View Post
I would think the very flat terrain makes it harder for trees to take root and grow.

If you think about the Great Plains, it's all pretty barren and that's across a very wide area, with all types of differences. Yet, the one common denominator is that it's all flat and pretty treeless.
Eastern Arkansas is every bit as flat as Oklahoma and huge, 80' tall trees are quite common once you get east of Little Rock. It's noticeable when driving west on I-40 from Memphis that the tree canopy gets progressively shorter once you get west of Little Rock until trees disappear nearly entirely in western Oklahoma.