The Ban Namjum community is able to manage its bio resources in many ways such as in the development of manufacturing systems, the knowledge of tropical plant selection, exchanging knowledge about local food consumption and the belief in spirits. From 1957, the community has faced 3 factors: the first is the government’s forest concession policy which persuades the villagers to exceed the community’s rules. The second is the promotion of commercialized agriculture as a model of modern production. The last is the government’s establishing property of rights for itself and for individuals. This lessens the rights of the villagers to use common property and this makes the villagers not feel confident about their livelihood. Furthermore, the community’s power for maintaining? and obstructing outsiders is lessened. These conditions force the villagers to adapt themselves to do many things such as gardening, growing vegetables, being labourers, both within and outside the community, reducing their use of shifting cultivation in favor of commercialized agriculture. However, it is found that the last one is high risk because when there is a full price mechanism, the villagers do not own their own products so there is a cycle of debt. Nonetheless, the social structure of the community can be united, they can consult, discuss and summarize their lessons in both their community and their network in order to search for alternatives to conserve the sustainable biodiversity and their community. “Hug Muang Nan” network is the organization which supports the community. (P. 113, 124-125, 134-140) The researcher uses population framework rationality, but there is also the government’s national sanctuary proclamation which is an internal force. These mainly cause the confidence in property rights within the group of villagers and are the former whereas the increasing of population is the latter. Besides, there is not any evidence to support and be noted in this research, for example, there is the increasing of population, but there are not any figures of withdrawal of over 5 Rais of land which is over and above the amount of land the villagers possess.