As the Memorial Day holiday weekend kicks off the summer camping season, New Hampshire authorities are reminding people it's illegal to bring untreated firewood into the state without a written agreement from them. 

It's also illegal to transport hardwood firewood outside of Rockingham, Merrimack and Hillsborough counties to prevent the spread of emerald ash borer, a destructive beetle that targets ash trees. 

Firewood is a major source of damaging insects and diseases and the firewood quarantine helps protect the health of New Hampshire's forests. 

Forest Rangers with the Division of Forests and Lands are enforcing the firewood quarantine this weekend with roadside checkpoints.