An afforestation and/or reforestation business system, which is capable of devising and evaluating an afforestation and/or reforestation business is provided. The system includes a communication system capable of communicating between a terminal at the business center and a terminal at respective local sites, a first database for storing records related to the afforestation and/or reforestation business, a second database for storing records related to tree species and the site information, a site determining portion for evaluating the proposed afforestation and/or reforestation sites using estimated carbon dioxide absorption amounts to be obtained by executing an afforestation and/or reforestation business, and a business plan determining portion for determining an afforestation and/or reforestation business by selecting an appropriate tree species and an appropriate area that can obtain the greatest profit and the greatest carbon absorption amount from the site.