A massive increase in forest litter and landfills during enclosure damages the countryside and costs £ 134,000 to clean up, a charity said.
The Woodland Trust said its more than 1,000 locations in the UK have remained open, giving people access to forests and local wildlife areas during the pandemic.
But an increase in forest visitors has also seen a huge increase in litter, fly chickens, and irresponsible and harmful behavior, the conservation conservation charity said.
The cost of clearing the damage comes at a time when financial institution charities have faced financial difficulties as a result of the lockdown.
And discarded waste can pose a threat to nature in many ways, the Woodland Trust said.
Plastics and metals do not naturally decompose and can persist in the natural environment for decades, changing the soil composition, while chemicals from more hazardous waste can leak into watercourses.
Animals can suffocate in discarded plastic bags, become entangled in plastic can holders and injured by broken glass or get stuck in pots.
Straying from designated paths can damage delicate old environments that take many years to recover.
But the Woodland Trust has seen even more harmful activities on some of its sites.
In Dering Wood, near Pluckley in Kent, people have cut and damaged trees, made camps and dropped trash and drug waste, and made fire pits – forcing the charity to close the parking lot to curb the problem.
At Ashenbank in Gravesend, including Kent, there have been similar problems, and people have even removed the protected large-crested salamanders to bring back to their ponds, the Woodland Trust said.
Other places where litter, fly hen or antisocial behavior have been observed include Skipton Castle Woods in North Yorkshire, Barber Wood, near Cheltenham in Gloucestershire and Smithills, near Bolton.
The Woodland Trust urged people to follow the rural code and take waste home.
Norman Starks, director of the charity, said: “It is great that people go out and visit our sites to enjoy the benefits of nature, which are so important in these difficult times, but we have a huge increase in clutter seen .
“The vast majority of people visit our sites with respect, but we have seen an increase in the number of people who abuse sites, such as setting up camps, cutting trees and other harmful activities, such as mountain biking on designated trails.
These are very vulnerable habitats; in some cases they are hundreds of years old. We need the public to help us continue to protect these environments. “
The Trust said it has spent over £ 1 million over the past seven years on clearing up debris and fly dumps in the forests, which is money that can be spent on planting and protecting wooded environments.