Composition of vegetation in Robian Tongah-tongah, Mount Sibuatan Protected Forest, North Sumatra

Abstract

Noviady I, Siwi SN. 2015. Composition of vegetation in Robian tongah-tongah, Mount Sibuatan Protected Forest, North Sumatra. Pros Sem Nas Biodiv Indon 1: 1380-1384. Mount Sibuatan Protected Forest is one of the mountainous forest areas which have very high diversity of plants in North Sumatra. At least 80 plant families were successfully recorded on various altitudes. Robian tongah-tongah is the forest area on Mount Sibuatan passed hiking trail. The aim of this study was to determine the composition of forest vegetation in Robian tongah-tongah. The observed vegetation composition was understory plants, seedlings, and trees. Data were collected using transect method with a quadrant analysis, each of 10 plots measuring 10 m x 10 m (trees with a diameter > 10 cm), 5 m x 5 m (seedlings and trees with a diameter < 10 cm) and 1 m x 1 m (understory plants).The results showed that at the level of tree
(diameter > 10 cm) Aglaia sp. were dominated with 32.14% of Importance Value Index (IVI) and Meliaceae family with 58.18 % of
IVI. The level of seedling and tree with a diameter <10 cm were dominated by Acronychia trifoliata with 14.54% of IVI and Lauraceae
family with 31.91%of IVI. Argostema involucratum was dominant spesies of understory plants with 88.30% of IVI.