Rich factual material has been amassed over the past quarter century on borderland ecosystems, their structure, spontaneous dynamics and consequences of human interference, including the territory of operating and planned protected areas (PA's). A very concise description of the natural characteristics of operating and planned (for which feasibility studies have been prepared) conservation areas and sites in the Karelian part of the Green Belt of Fennoscandia (GBF) is provided and their present-day state is assessed. The material is roughly structured as follows: 1) location, year of foundation, size (according to foundation papers / or forest management inventory - where the boundaries are not clearly marked out); 2) purpose of establishment; 3) landscape characteristics and shares of land categories; 4) forest genesis and age (forested areas dominate in almost all PA's in GBF); 5) presence of red-listed species; 6) specific features (recreational appeal, amount of visitors, etc.); 7) current threats and recommendations on how to eliminate or minimize them. Based on these materials, we evaluate the various aspects of the PA system of the Karelian GBF, first of all its sufficiency as the region's ecological framework. The aspects considered are its representativeness in terms of landscapes, the share of undisturbed natural ecosystems, presence of areas highly vulnerable to human impact, recreational appeal, cross-border spatial connectivity, and others. As a result, we argue that the PA system formed in GBF by now (planned areas included) is quite representative and extensive. In our opinion, its further development should consist in saturating the GBF with relatively small (hundreds and thousands of hectares), highly valuable areas situated in-between the existing PA's.