From the U.S. Forest Service:

Due to the lapse in federal government funding, the U.S. Forest Service is operating with minimal staff to ensure certain essential services. 

All facilities, including Forest Service offices and developed recreational areas such as campgrounds and picnic areas are closed. General areas of the National Forest where you may drive, hike, hunt and fish remain accessible.

For further information on how the government shutdown is affecting the Forest Service, please refer to information provided here:

Also - the U.S. Forest Service Lake Tahoe Basin Management Unit is closing Forest Service-operated facilities and cancelling Forest-Service staffed events due to the lapse in federal government funding, effective October 1, 2013 until funding is restored.

Concession-operated facilities, campgrounds and events will continue as normal for the time being. Most forest roads and gates remain open for the time being. The Forest Supervisor's Office and Taylor Creek Visitor Center are closed. Forest Service-operated campgrounds are closed. Cancellations include this weekend's Fall Fish Festival. Law enforcement and fire suppression personnel remain on duty.

And - Tahoe National Forest offices, including the headquarters in Nevada City and ranger district offices in Camptonville, Foresthill, Sierraville, and Truckee, are closed until further notice because of the lapse in federal government spending.
All fee campgrounds that are concessionaire-managed are open until scheduled to close for the season. Other recreation facilities are closed and will not be maintained during the government furlough.
Forest woodcutting hotlines will still be open, and persons with current fuelwood permits may continue to gather firewood as conditions allow.
The Tahoe National Forest Web site at will still be live, but information will remain static except that which concerns public health and safety.

From the U.S. Forest Service