The Penhydd mountain bike trail at Afan Forest Park will close on 12 April so Forestry Commission Wales can carry out tree thinning work.
Once forestry operations are completed, which is expected to take about a year, a redesigned trail will be built, which will use some of the original route.
Mountain bike ranger Carl Denham said: "Although this trail will be closed for a year or so, it gives us a great opportunity to refresh the route, which was created 10 years ago by local mountain bike club Singletrack Mind.
"It’s hoped that the work in the forest will help to open up new areas that can be used for the rebuilt Penhydd Trail and even the planned blue-graded trail."
