The new Forest Inventory ESTimation and Analysis system (nFIESTA) is an open-source PostgreSQL extension capable to produce estimates of target parameters describing the condition of forests and its development. The specificity of the nFIESTA estimation system is that it allows for an analysis of large datasets sourced by National Forest Inventories (NFIs) of many (not only European) countries. Such an integrated database contains sample plot data that use to be collected following a number of different sampling and survey designs, with spatial distribution and timing that vary from country to country. Using such a system the estimates of forest and landscape parameters can be obtained at a level of detail starting from a relatively small areas - as small as several hundreds of sq. kilometers. From the temporal point of view, the current implementation supports estimations for periods of one calendar year or longer. The system was designed and developed so it can use various sources of auxiliary information (typically GIS maps produced by remote sensing methods). The SW has been developed as part of the Diabolo project (http://diabolo-project.eu/) funded by the European Union’s Horizon 2020 research and innovation programme. Here is the link to the git repository: https://gitlab.com/nfiesta and presentation slides: [odp](https://gitlab.com/nfiesta/nfiesta_pg/wikis/myuploads/FOSS4G_Bucharest/nFIESTA__FOSS4G_2019.odp), [pdf](https://gitlab.com/nfiesta/nfiesta_pg/wikis/myuploads/FOSS4G_Bucharest/nFIESTA__FOSS4G_2019.pdf).