Lontar tree is one of the biological resources that ecologically has a wide and varied distribution. From the description of Beccari (1913), palm leaves which are growing in Indonesia are Borassus Sundaicus. Lontar tree is a dry land resistant plant that has a wide spread, grows in several areas in Indonesia such as in the eastern part of Java Province (i.e. Madura), Bali, West Nusa Tenggara Province, and East Nusa Tenggara Province (Nusa Tenggara Timur or NTT). NTT is a natural distribution area of palm oil, namely on Timor Island, Flores, Sumba, Savu, Rote and other Islands including in the West Timor Island (Kupang City). For the people in Kupang City, lontar tree is more familiar with the term Tuak tree (Timor’s language) or Palm Tree. Tuak tree has benefits for the culture, social, health and economy of the community. However, with various benefits, of course there are problems, namely the existence of threats to the sustainability of its existence. The development in Kupang City has converted the land where Tuak trees are grown for the benefit of government offices, the private sector, residential settlements, the economy, and other public facilities. The threat to the preservation of Tuak trees is also seen in the mindset of local governments and communities who hold firmly a perspective that the Tuak tree is very difficult to be cultivated by the community because it has a natural resistance to its life. The result has been patterned in the community, that the Tuak tree can grow without being planted and mantained. From a legal standpoint, the regional legal norms seem to support the act of transferring the land of the existence of the Tuak tree, even though, the Indonesian national environmental law explicitly instructs legal regulations to take into account the interests of environmental sustainability. The purpose and contribution of this research is to analyze the readiness of regional legal arrangements regarding Green Open Space related to the protection of the carrying capacity of the Tuak tree in its conservation. The contribution of this study as a basis for the consideration of the Indonesian government and the community in planning the establishment of regional laws to support the protection of the Tuak tree in NTT, especially in Kupang City, as well as further research material in the area. This research method was designed as normative and empirical legal research. The normative direction questions the legal regulation aspect from a juridical technical point of view (Dutsch: Tecnischjuridisch begrippen) and also in the realm of legal theory the question of the concept of legal protection for the Tuak tree is questioned. In strengthening conceptual aspects, an empirical legal thinking is inputted to strengthen the conceptual analysis of legal norms. This study uses the Statue approach, Conceptual approach and Case approach. The sources of legal material are in the form of primary and secondary legal materials. The aspects that were studied are the provisions of conservation law related to tree management and protection in order to protect the green open space in Kupang City, where the legal provisions governing follow-up products from the Indonesian national and regional management, determination of Indonesian regional policies relating to management, cultivation, conservation of the Tuak trees and determination of programs related to the conservation of the Tuak trees, which are associated with protection planning policies, conversion of crop land, protection of local food, other follow-up products from palm wine stems and leaves. The results of the study show that the norms in the Kupang City’s Regulation Number. 7 Year 2000 concerning the Green Open Space contain more spatial concepts than the green concept of the existence of the Tuak tree as a biological resource. The word "green" refers to trees or plants that live and grow in Kupang City, but in its implementation, the Indonesian regional law dominates these regulations which are supported by an Indonesian policy that always changes due to a pressure on land requirements for development in Kupang City. The regional legal planning for the law protection of the Tuak tree in Kupang City has not received serious attention yet from the Indonesian regional legislative and executive councils. The legal plan for the protection of the Tuak tree is supposed to be carried out under conditions where the population of the Tuak tree has not been disturbed naturally through its management various development interests in Kupang City, in the West Timor Island, East Nusa Tenggara Province, Indonesia.