1. Akita prefecture, Forestry statistics of Akita prefecture in 2010 (2011) (in Japanese).
2. Akita prefecture, Statistics of forestry in 2010 (2011) (in Japanese).
3. Aomori prefecture, Forest and forestry of Aomori in 2009 (2009) (in Japanese).
4. Cabinet Office, Government of Japan, 5th Agriculture, forest and fishery TF (2009) (in Japanese), available from <http://www8.cao.go.jp/kisei-kaikaku/minutes/wg/2009/0714_02/item_090714_15.pdf> (accessed on 25 February, 2012).
5. Chugoku Bureau of Economy, Trade and Industry, Report of utilization of domestic lumber, forest residue, and thinned wood (2007) (in Japanese).