Even though the aim for natural forest management in Dong Nai natural and cultural conservation area had been changed nearly 10 years ago, but most forest area has not been transformed looking at it from a technical perspective. One of the causes of this problem is the lack of scientific data about characteristics of forest plant communities. That is why this paper focuses on addressing this issue. Based on data collected on 15 sample plots in 2011, which are representative of 2 types of forest plant communities, the paper clearly described four characteristics of forest plant communities: (i) important value of tr,ee species
(ii) tree species diversity index
(iii) relationship within tree species
and (iv) quantitative relationship between forest inventory factors. The results showed that, there are 10 to 13 tree species having ecological significance in communities
P. chinensis, L speciosa, X noronhianum and C. ligustrinum are four species having the highest important values. Tree diversity was considered at an average level. With the similarity of 80 percent, the cluster dendrogram showed that species having mutual 'relationship such as X. noronhianum and P. chinensis, D. venosa and L leucacephala. Based on MNDS, tree species were divided into 8 groups. From PCA diagram, tree species were divided into 4 groups, of which each species within a group having good relationship with each other. However, tree species in group 1 and 2 shows a competitive relationship with ones of group 3 and 4, respectively. Quantitative relationship between forest inventory factors was simulated by fuzzy regression models with relative errors from 3.4 to 18.5 percent. Generally, forest plant communities in the study sites have a good rehabilitation capacity and the transformation of forests in term of silvicultural techniques to meet the new aim and requirement of forest management is highly necessary as well as significant.