Which geographic regions did the cross timbers once cover?

The geographic region between the "eastern deciduous forests" and the "grasslands of the southern Great Plains" was once covered by Cross Timbers.

Explanation:

The pre-settlement Cross Timbers were spread over an area as big as 28,000 square miles. The region between the "eastern deciduous forests" and the "grasslands of the southern Great Plains" is believed to have been once covered by the Cross Timbers. Clearing of the land for settlement purposes and to fetch economic gains from the forest produce, unregulated cutting of the Cross Timbers happened fro years which resulted in heavy depletion of this ancient forest. Now the Cross Timbers only exist in the shape of a narrow strip of stretching from Central Texas to Southeastern Kansas, covering the Central part of Oklahoma.

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