Investigators are working to find who is responsible for illegally chopping down trees on Suffolk County park land on Shelter Island.

Jean Lawless, a resident of the area for 50 years, tells News 12 that she made the discovery one day back in mid-January as she walked her dog. She saw that trees had been cut down in the area of Hay Beach, and she immediately alerted the authorities.

Drone footage shows the affected swath of forest, from the area of Menhaden Lane down to the bay. Some of the affected trees had their tops cut off, while others were completely felled.

"Some of them are 40-year-old cedar trees, Russian olive, all of which feed the birds and animals there," Lawless says. "Whoever did it, whoever's responsible, they've just really destroyed a beautiful forest."

It amounts to about 4 acres of coastal forest, all felled with a chain saw. Lawless says she counted more than 100 affected cedar trees.

"Everybody should be upset about this," says Shelter Island environmentalist Tim Purtell. He says the trees that were destroyed protected the coast from erosion and provided food and shelter for birds and animals.

There are two homes that abut the swath of affected forest. News 12 knocked on their doors to see if the residents knew anything about the chopping, but no one answered.

Suffolk County Police Department's environmental unit confirms it is investigating, but further details have not yet been released.

"I'm glad the county's considering it a crime, because it is -- a crime against nature, a crime against all of us," Lawless says.

Those responsible could be fined thousands of dollars per tree that was taken down.

Menhaden Lane Dunes Tree Cutting Aerial Drone Footage 01/29/2018 from Bran Dougherty-Johnson on Vimeo.