(VNA)- Experts from the International Union for Conservation of Nature (IUCN) have toured three provinces to prepare the dossiers of the Cat Tien National Park for UNESCO recognition as a world natural heritage.  The experts held working sessions with leaders of Dong Nai, Binh Phuoc and Lam Dong province yesterday and will inspect the park and meet residents of its buffer zones until Wednesday.  After that, they plan to interview the people and authorities of the three provinces about conservation management work at the park.  Covering over 71,900 ha in the three provinces, Cat Tien National Park is now one of the six world biosphere reserves in Vietnam and one of the four nominees for UNESCO recognition as a world natural heritage.