Intensive management in European forests in the 20th century resulted in the elimination of the old-growth natural forests on vast territories. Since then, the forests have been mainly cultivated, however, the spatial structure and tree species composition of the planted forests are simplified that makes the forests more vulnerable to diseases and disturbances. The old-growth natural forests that better suited for the local environmental conditions remained only in some isolated places or where the infrastructure was not developed. The old-growth natural forests can be used as etalon (model) forests for the reconstructed managed forests in similar environmental conditions. We studied spatial structure, biodiversity indicators, and carbon stocks of the old-growth natural forests in the protected areas of the Ukrainian Carpathians, in particular Nature Reserve ‘Gorgany’ and National Nature Park ‘Skole Beskids’, for setting forest management targets for the forest plantations in the region. We made detailed measurements on the experimental plots randomly selected from a regular grid and applied remote sensing data (Landsat and QuickBird) for upscaling the results to the whole territory. For selecting the locations for the experimental plots, we used data from the 2011 National Forest Inventory for choosing the potential stands with average age of more than 120 years. We estimated the carbon stocks from the forest inventory data, that performed for the experimental plots. For estimation of the biodiversity and spatial patterns of tree locations on the experimental plots, we employed Clark-Evans, Donnelly, Shannon, ‘angle’ and ‘differentiation’ indexes. At the end we present detailed results of our study and discuss a development of a database of parameters of old-growth natural forests and environmental parameters that could be used for setting forest management targets in different locations.