The forest in the province of Misiones, northeastern of Argentina, is a portion of Paraná Forest (or Atlantic Forest) located also in the south of Brasil and Paraguay. At the beginning of the last century the native forest had an extension of more than 100.000.000 ha. Actually, Brasil preserves only the 5% and Paraguay the 10% very spoiled and fragmented. In Argentina the decrease was the 45%, and keeps in existence 1.422.661 ha (National Forest Inventory 2003), with the higher values of biodiversity of the country. This area in Argentina has an accelerated rhythm of urbanization and deforestation. The productive system in the zone provides between 70% to 85% of wood to national market. Recent studies of diversity and dynamic of the native communities are very limited. For these reasons it’s necessary to increase the spatial information of the natural resources, the expansion of human activities and the disturbances in the environment to improve the management, the arrangement of territory and the tools for the decisions makers. The main objectives of this study were: to analysis spatial and temporally the structure and dynamic of forest in the Valley of Cuña Piru (sector of Atlantic Forest, Misiones), and to compare different methods and tools in order to develop an efficient and operative methodology for a systematic monitoring of the status/condition of the area, by mean of satellite images analysis (Landsat and Aster) and GIS techniques (modeling, mapping of changes, identification of plants structures and physonomy by different classification methods). The preliminary results showed an operative and efficient methodology with remote sensing tools for the forest monitoring and a preliminary protocol of processes was developed.