What geographical feature divided Oklahoma into different parts, primarily forests and thickets?

The Cross Timbers is the geographical feature that divides Oklahoma into different ecological regions, primarily creating a contrast between forests and thickets. This area forms a natural boundary running roughly northeast to southwest across the state, separating the eastern portion, which is characterized by more wooded and forested lands, from the western portion, which is primarily part of the Great Plains with open prairies and fewer trees.

The unique composition of the Cross Timbers, consisting of a mix of post oak and blackjack oak trees, contributes to the diverse ecosystems found within Oklahoma. This transition zone supports various types of wildlife and plant species, emphasizing the ecological significance of this feature in the state’s geography.

In contrast, the Great Plains are expansive flatlands primarily to the west, while the Red River serves as a natural boundary between Oklahoma and Texas. The Ouachita Mountains, located primarily in southeastern Oklahoma, provide a distinct topographical feature but do not serve the same dividing function between forests and thickets as the Cross Timbers does. The Cross Timbers specifically highlights the combination of both forested and open landscapes within Oklahoma’s geography.