Japan Center for International Cooperation in Conservation has been doing researches on the deterioration and conservation of outdoor cultural property in Southeast Asia since its foundation. Now we conduct joint researches in Thailand, Cambodia and Indonesia, as well as the UNESCO-Japan Funds in Trust Project for the protection of Thang Long Imperial Palace in Vietnam.

The climate of the Southeast Asia is mainly tropical or subtropical. The area has distinguished dry and rainy seasons. Plants grow very rapidly especially in rainy seasons and control of growth of plants is difficult. To consider the conservation of cultural property, it is inevitable to understand not only the characteristics of cultural property itself but also the micro- and macro- environment which causes the deterioration.

Unlike the storage buildings such as museums, control of outdoor environment is difficult, so we must be careful to intervene directly to cultural property and consider how to minimize the influence of the treatment. Conservation treatment is never almighty or everlasting. We must take into account of the effectiveness of the passive way like daily maintenance. It seems to contradicting but we also consider it necessary to find the better environment for conservation of cultural property in observing the condition in detail so that we will be able to extend such condition to other cultural property.

We continue the researches with detailed observation of the characteristic environmental condition of the region as well as utilizing our experience in Japan. On the other hand, we believe the experience in Southeast Asia where the environment is very severe will be useful to the conservation of cultural property in our country.