|| 要旨トップ | 目次 |||日本生態学会第64回全国大会 (2017年3月、東京) 講演要旨
一般講演（口頭発表） K02-09 （Oral presentation）
Illegal logging is a very serious problem for plantation management in tropics. Here we study the role of the profit sharing and agroforestry as management strategies in mathematical models. The owner chooses the age of trees to cut, and the local people choose their monitoring effort to prevent illegal logging. After the trees were removed, either by cutting, physical disturbances, or illegal logging, the owner hires local people to replant young trees. While trees are young, the land is also used as agriculture. In addition, the owner may share a fraction of profit obtained by selling logs with the workers. Illegal logging may be prevented by hiring forest guards or by monitoring effort of the workers. Results are: (1) If the discount rate is high, the foresters may use the land for continual agriculture by cutting trees at their young ages. (2) Under the presence of illegal logging pressure, the owner may find it profitable to share the income with the workers to solicit their monitoring efforts. (3) An increased cost of replanting makes local people reluctant in participating in surveillance activity, and makes owner increase the profit-sharing rate to encourage their participation. We discuss policy implications of these results.