A circuit that is fully surrounded by forest is the Sodegaura Forest Raceway in Chiba prefecture. To emphasize the natural spirit, there have been planted 10000 trees in the center of the circuit. The circuit was build in 2009 and certified according FIA regulations.
The length of the circuit is 2436 meter if the full course is driven (so not only the outer part) with a total of 14 corners. The main straight is 400 meter long. Usually the circuit is driven clockwise.
In case there are no special events scheduled, it is possible to drive yourself on the circuit. A first time admission should be paid which is 10300 Yen. I one year license can also be obtained for 15500 Yen. A license workshop will then be held, with in the morning car inspection and a classroom training, and in the afternoon free driving. A 30 minutes drive on weekdays is 3600 Yen and in the weekend 4200 Yen. A maximum of 35 cars can be on the circuit at the same time.
On the inside of the circuit is also a restaurant called Greenwood. It looks out on the final corner before the straight. The circuit is approximately 1 hour driving by car from Tokyo. If you want to go by public transport, it is then best to go to Higashi-Yokota Station or Kazusa-Ushiku Station but from both stations it is approximately 1 hour and a half walking.
A link to the website can be found below:
http://www.sodegaura-forest-raceway.com/index.html
And a link to the location on Google Maps:
Sodegaura Forest Raceway Google Maps link