Jolly Nose Mountain Bike Park, located in Queens Lake and Burrawan State Forests, is a popular spot for mountain bike riders of all skills and abilities, from elite riders to families.

The area is managed by the Hastings Valley Mountain Bike Riders under a permit with Forestry Corporation, which allows the group to construct and maintain single mountain bike trails through the forest.

The club and Forestry Corporation are concerned that the damage appears to be intentional.

Many volunteer hours have gone into building these trails, making the area a sought-after location for statewide and national mountain biking events.

The club is also growing increasingly concerned for the safety of mountain bikers, said President Mick Fullbrook, with the vandalism following some increased interactions with trail bike riders on the approved mountain bike trails.

"One of our most popular gravity trails has had trail bikers riding up it, so there's a real chance of a collision."

Forestry Corporation's Partnership Leader Sandra Madeley said that State forests are for everyone, but people need to behave appropriately, consider the safety of others and follow the rules.

"We manage State forests for multiple users and the mountain bike park can coexist with other forest visitors," Ms Madeley said.

"We're so disappointed to see the vandalism of approved signage, and will monitor the area carefully and cooperate with police.

"Registered and licenced trail bike riders can ride in State Forests on formed roads only. That's the law. The Jolly Nose purpose-built mountain bike single trails are for use by mountain bikers, including the club and local community."