VOORHEESVILLE, N.Y. (NEWS10) — Have you seen those black bags on the ground around Thacher Park? The park said they are buckthorn baggies.

Buckthorn is a small tree or large shrub that has small thorns at the tip of its branches. Common buckthorn is considered an invasive species throughout most of the northeastern United States because of the dense thickets it forms.

The bags deprive the stump of the buckthorn shrub of sunlight, therefore killing them off. The park requests that visitors do not touch the bags and leave them where they are.

“Although slightly unsightly now, once the buckthorn is killed off, native plants will have a chance to take hold,” said park officials.