Truth and definition on land is a strategy of power and power relationships that can well conceal an actual land power operation. In today’s society, an expression of land power and control of resources by means of force and violence cannot be legitimized and be accepted by the doees and the global community. Therefore, actual operations of each power group focus on strategies to conceal their real needs, as shown in the truth and areal definitioin that the state gave to those fighting the Communist Party of Thailand. In the power dimension and context of power relationship, legitimization indicates ownership rights and land ownership as an individual and family asset. State agencies and NGOs working for hilltribe development projects create the truth and areal definition as a forest conservation zone. However, the implication is the legitimization of their actual power operations to designate forest conservation zones, reforestation and land control for production. For the Lahu, such truth and definition reflect their struggle to create confidence and life security. The struggle is not baseless, but the truth and definition are elements in the power contestation in producing or creating the truth and definition of the area. Whether the truth and definition are true or not depends on actual power and operations in reproducing, directing, controlling and distributing the definitions of truth. For the Lahu, the contestation is not only to create areal truths according to physical geography to express land power and resource management control; it also implies the symbol system to express their rights and dignity as human beings and citizens of the state. It also creates mental, life and socio-economic stability as well as confidence in life in this world and the future world. The contestation is also a struggle arena to create its ethnic identity. Under the contexts of state power structure and market system, the ethnic group has been deprived of production factors and socio-economic independence as well as being ethnically assimilated. However, with techniques to create the ethnic identity under such conditions and contexts, the implementation of forest conservation activities has become a platform for the ethnic group to define itself as “the forest conservation Lahu Thais” in an attempt to create the security and confidence of their position in the new socio-economic and cultural systems.