(AP) — Nebraska’s state tree, the cottonwood, may struggle to thrive in the Cornhusker state.

University of Nebraska-Lincoln Extension forester Dennis Adams says the cottonwood is threatened by several factors in the state.

The cottonwood needs bare mineral soil to regenerate, and that is common after flooding. Adams says modern flood control efforts make it harder for the trees to reproduce.

Adams says cottonwoods can also be damaged by livestock grazing and by herbicides used in nearby farm fields.