Work is taking place at South Barrule Plantation to remove storm damaged trees.
DEFA expects the work to take several months to complete, with fencing and public notices in place to show any diversions or restrictions.
The department said it's aiming to keep the main forest roads open, but some restrictions will apply at times.
The Viking mountain bike trail will be closed throughout the works.
South Barrule's outdoor activity businesses will operate as normal.