Visitors to Bradley Woods have been urged to act responsibly as visitor numbers increase as lockdown is eased.
Some people driving to the site are blocking the single-track access road by parking badly.
Motorists are asked to avoid stopping if the car park is full or try visiting on foot or by bike instead.
Historic Bradley Woods is one of North East Lincolnshire’s most important sites for visitors and wildlife.
The ancient woodland is over 1000 years old, and was mentioned in the Domesday Book, and has remained largely unchanged ever since.
Perhaps more importantly, the woods also inspired Grimsby’s coat of arms.
The three boar heads which represent the borough are believed to have links to Henry VIII, who is said to have hunted in the woods while staying at nearby Thornton Abbey in 1540.
Bradley Woods is one of four irreplaceable local nature reserves, alongside Weelsby Wood, Cleethorpes sand dunes and Cleethorpes Country Park.
Many species, including birds, beetles, bats and badgers, call the woods home, and are a large part of why the area is so important.
Deer also use the woods as a refuge and badgers forage for food on the woodland floor.
Work is currently underway to identify hazel dormice in the woodland, a rare and protected species which can be very hard to find.
More than 130 different types of beetle have been found in Bradley Woods. The insects lay their eggs in dead wood and are important part of the eco-system, often as food for birds.
The most common beetle species have declined by 75 per cent across the UK since 1970 and several are endangered, verging on extinction.
Different flower species, including bluebells, lesser celandine, wood anemone and dog’s mercury, which grow in ancient woodlands are all present in Bradley Woods.
Councillor Stewart Swinburn, cabinet member for environment at North East Lincolnshire Council, said: “Protecting the ancient woodland is a priority for North East Lincolnshire Council.
“Visitors to the woods are welcome, but should be considerate when and take care to keep dogs under control at all times.
“People have recently been found blocking the single-track road in and out which causes problems for others, especially Council vehicles carrying out important work at the site.
“If the car park is full, please don’t stop or block Bradley Road. Please also stick to the paths to avoid disturbing protected species and potentially committing a criminal offence.”
Taking or removing wood from the area is criminal damage and you can be prosecuted for disturbing bat roosts or nesting birds and dormice.
North East Lincolnshire Council ecology manager, Rachel Graham, said: “Ecology officers have recently had to remove sycamore trees planted in the woodland.
“While sycamore is naturalised, it spreads prolifically and can out-compete other trees which would cause significant damage to the precious ancient woodland.
“It’s also hard to know what is being transferred with the soil that brought in, it could be detrimental to the precious and rare habitat.
“Bradley Woods is predominantly oak, a native species, and has been for more than 1000 years. Please don’t plant anything or do anything that would risk the future of the woods.”
Mycorrhizal fungi thrive in the area, which are beneficial to trees and plants.
The fungi take sugars from plants and provides moisture and nutrients for the soil, effectively acting as extensions to plant roots and make the woodland function.
Hundreds of years’ worth of leaf litter has collected in the woods to create these very rare conditions which only 1000 years of nature can produce.
The woodland is a semi-wet woodland, a very rare type of habitat, with a series of deep ditches and temporary pools.