1.   Eastern grasslands are wet enough for forests, but frequent fires knock down woody vegetation while letting grasses persist, Johnson said.

2.   Fifty young people from the Student Conservation Association and the Montgomery County Conservation Corps began clearing out the woody vegetation from culverts and locks of the canal.

3.   Fires set by lightning, or more recently by people, help grasslands stay free of woody vegetation and restore vitality and species diversity.

4.   Typically, these ecosystems are inhabited by such native woody vegetation as willow trees, cottonwoods, and mesquite.