Subregions Distinctions between these subregions may be summarized as differences in the degree of development of the oak-hickory forest. The Western Cross Timbers is the least well-developed due to the lessened availability of moisture. Forests here are neither as dense nor as tall as those in the Eastern Cross Timbers. There are fewer eastern species here. Pockets of deep clay soils support bluestem prairies.
Gray squirrels occur only in hardwood bottoms.
The Oak Woodlands contain the best developed oak-hickory forest in Texas. Gray squirrels are abundant. Prairies are more common than in the other subregions. The peat bogs mentioned above are found here. The Eastern Cross Timbers is best described as a mix of the Western Cross Timbers and the Oak Woodlands.