A savanna is an ecosystem with trees, but an open canopy allowing grassland plants to dominate. A forest or woodland has greater canopy cover, shading out other plants.  It is estimated that it may take several hundred years to transition from sand to oak forest. The sandy soil limits the growth of the Black Oaks, so those at Illinois Beach are smaller than others in Illinois. Black Oaks are often hollowed out in the trunk, providing shelter for birds, mammals, insects and more.

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