ST. JOHNSBURY, Vt. (AP) – The Vermont Department of Forest and Parks is seeking ways to fight a nonnative invasive species that some feel could threaten the state’s forests.

Glossy buckthorn bushes and common buckthorn, were once promoted by the state as a way to control erosion, but now they can prevent the growth of young trees and they are hard to eradicate.

“They tend to leaf out first,” said state forest protection chief Scott Pfister. “And they stay green longest. You get a plant that is able to out-compete a lot of the vegetation that is around it.”

A thicket of buckthorn doesn’t harm mature trees, but it will make it harder for the next generation to grow up.

Last spring the Legislature added a provision to the state budget requiring the commissioner of Forests, Parks and Recreation to come up with a plan for control and eradication of buckthorn.

Experts say the best way to get rid of buckthorn is by digging it up, using herbicides or a combination. Whatever is chosen, it’s a long-term process, said Sara Kuebbing, coordinator of the Champlain Basin invasive plant partnership for the Nature Conservancy.

“They will keep coming back,” she said. The best option is early prevention and early detection, officials said.

State officials and other groups met last week in St. Johnsbury to discuss the problem.

“I would propose manual removal,” said St. Johnsbury deputy Tree Warden Andy Fisher. He suggested using volunteers to chop down buckthorn along the trails in the town forest. “It will build support for whatever other methods we are going to be using.”

Others suggested herbicides or manual control.

“There are lots of small-sized plants out there that could be pulled out,” said state forestry Specialist Kathy Decker. “The larger plants are a big concern. Those are the ones producing seeds.”