Mount Ciremai National Park forest that area had been encroached. Because of that condition, stand structure especially the species composition and vegetation structure need to be researched. The aim of this research was to identify plant species and analyze forest vegetation structure. This research was conducted between March–April 2018 in the 15.500 ha area with 0.02% sampling intensity. Data was collected using grid line method that consisted of 34 sample plots with the 10 m distance between the plots and 20 m between the lines. The numbers of identified plant species at the research location were 43 species, classified by 10 families and 24 genera. Cinnamomum sintoc has a high level of dominance species. The forest vegetation was consisting by the different growth phases. The tree phase has the highest density of 3672 species/ha, while the seedling phase was lowest density of 1060 species/ha. The forest crown stratification were consisting of A, B, C, D and E stratum. The highest number of plants were from C strata for 4651 trees and the least from A strata with 25 trees with the highest tree was 42 m. Could be concluded that the composition of Mount Ciremai National Park forest have so many number of species and complex structure vegetation forest.

The Perhentian Island Archipelago comprising of 11 small islands is located in the state of Terengganu are among the biodiversity rich localities in Peninsular Malaysia. Perhentian Besar with approximately 867 hectares is one of the inhabited island and become the centre of tourism besides Perhentian Kecil. Island is well known as a place for many endemic and endangered living organism as previously demonstrated on other similar forested islands in Southeast Asia. However, there is little attention and effort of protection has been received by the terrestrial ecosystems that reside nearby the coastal. Thus, the present study investigates on tree diversity, stand structure and community composition in the island of Perhentian Besar, Terengganu. Forest plot of 0.5 hectare was established to analyze the floristic composition of tree taxa. The plot was divided into 10 subplots of 25m x 20m. All trees with 5cm diameter breast height (dbh) and above were tagged, measured for dbh size, recorded and identified. Voucher specimens were taken for further verification purposes. A total of 102 tree species were recorded comprising of 28 families and 65 genera. Rubiaceae had the highest number of species (11 species) and with regards to relative dominance, Shorea leprosula (Dipterocarpaceae) gave the highest importance value index (IVi) for species with a value of 8.45%. The Shannon-Weiner Diversity Index (H’) was considered high in the present study with 3.94 (H’max = 4.62) and the Evenness Index (E) value of 0.85 indicated that all species in the present study are almost equally abundant. The forest stand structure had a reverse J-shaped curve for tree size-class distributions as frequently observed in many natural forests, which indicated that the forest stand in the study site had a good recruitment patterns and also a main feature of matured forest in Peninsular Malaysia. The present study will help us to understand the pattern of tree species composition, diversity and forest ecosystem dynamic in Pulau Perhentian Besar.