Those places along former Iron Curtain profited from their inaccessibility. The moment Iron Curtain fell and fences and guards on borders were removed, it just turned into "normal" forested places and many of them got very frequented by tourists, new roads and other architecture was built in them. Eco-tourism haha. Small town Kvilda in Šumava (Czech/German mountain range) used to be sleepy rural place at the end of the world with few hundred people. Last year, national parks information center located in Kvilda alone got over 1,2 mio tourists, in year 2015 it was just 800.000. Basically local tourism grows 20% each year. Many forests also see very intense logging because those trees (old 70-80 years, they started to grow around WWII and after its end) are ideal for profitable wood production. People are degrading quickly the whole area of former border. Two small examples:
Moose population in South Bohemia withered and is basically extinct now (car crashes, disturbance by loggers and tourists, rest shot by Bavarian hunters because Bavarian law doesnt see moose as protected species).
The relict capercaillie population in Šumava is down under 500 und decreasing, they cant withstand disturbance by all that new intense tourism (mountain bikes, skiers everywhere, hiking with dogs etc.).
Reintroducing these two species now for example would have little sense in current condition of so called Green Belt. Each square mater in this country has its owner and the whole area is milked as much as it gets. Agriculture got so much more intensive thanks to huge EU subsidies. Logging runs at unprecented rate in recent 2-3 years. Prosperity supports mass tourism, both by foreigners and locals. Booming economy leads to massive construction on former rural lands.
That article sounds like some self-serving propaganda. Situation of natural landcape is much more dire and getting worse, especially in those former forbidden zones - change is very visible there.