INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 5, ISSUE 11, NOVEMBER 2016 ISSN 2277-8616 165 IJSTR©2016 www.ijstr.org Study On Vegetation And Its Habitat Conditions In Undisturbed Forest Budi Utomo, Afifuddin Dalimunthe, Ameilia Zuliyanti Siregar, Christovorus Sintong Situmorang Abstract: Now the flood has become a regular thing every rainy season arrives. But the longer, apparently extensive flood-affected areas is increasing with duration longer time. Even now in certain areas, the rain which lasted 1 hour is sufficient cause inundation. There are continuous efforts to overcome the flooding problems, but it seems the problem of flooding rather than diminish even more to improve the intensity, frequency and spreading. We tried to learn about the condition of undisturbed natural forests and how to treat rain forest. The study was conducted in the undisturbed natural forests namely Simpulan Angin forest situated in Deli Serdang, North Sumatra, Indonesia. The results show the undisturbed forest has 4 stratum layer of vegetation canopy. Humus in undisturbed forests has a thickness of 9-14 cm evenly distributed on the forest floor that serves as a giant sponge to absorb and store rainwater. This means that the undisturbed forest can absorb rainwater> 3,000 tons m 3 ha-1 every time it rains. Index Terms: undisturbed forest, vegetation, humus, thickness, rainwater. ———————————————————— 1 INTRODUCTION The forest is an ecosystem unity with the landscape with natural resources and composed by many components, and each component can not be separated even interdependent and affect one another. Forests in the role of great benefit for life, both tangible benefits are felt directly, or intangible perceived indirectly. The immediate benefits such as the provision of timber, wildlife, and mining products, while indirect benefits such as recreation benefits, protection and water regulation and the prevention of erosion (Nopandry et al., 2005). Today the major urban areas often floods during the rainy season. Heavy rain in just one hour alone can soak settlements and the associated infrastructure. Maintenance draenase trench was not much help cope with the recent flooding in the rainy season. This is contrary to the condition of the city in ancient times when population growth has not been as fast as today (Kompas, 2014). Insistence increasingly rapid population growth forced us to reexamine the ways to overcome the threat of floods. In the future with the rapid population growth will drive the growth of settlements and infrastructure, which of course will be covering the floor city into concrete and asphalt which further reduces the pore space where rain water infiltration into the soil. Therefore, through this study, researchers aimed to learn about the condition of undisturbed natural forests and how to treat rain forest. The results of this study will be the beginning of knowledge for researchers to replicate the same thing in the densely populated city. METHODS This research was conducted in undisturbed forest namely Forest of Simpulan Angin located in Dostrict Deli Serdang, North Sumatra Province, Indonesia. This forest is part of the Bukit Barisan Forest Park which covers 51,600 hectares. This forest is located at an altitude of 700 meters above sea level and is about 60 km from Medan city as the capital of North Sumatra Province, Indonesia. But the difficult road conditions cause travel time to study can reach 4 hours. The study took place from June to August 2016. Ancillary equipment used in this study include: hoes, shovels, machetes, tripe, chisel, measuring tape, phiband, haga meter, GPS, handcounter, 5m handmeter, tallysheet, cameras and stationery necessary. Research procedure The study was designed consisting of fieldwork and laboratory research. The field research in the form of activities in the forest vegetation analysis, observing the thickness of humus, to long lateral roots few dominant tree. While laboratory studies such as the calculation of forest humus ability to absorb water. 1. Analysis of Vegetation Vegetation analysis in this study using lines of procedures following the procedures Kusmana (1997). Paths defined by 5 lines with spacing between lines is 50 m. Long lines were made along 100 m so that there will be five pieces of plot-level tree on each track. Each piece is created nested to estimate the level of seedlings, saplings and trees measuring 2 x 2 m, 5 x 5 m and 10 x 10 m. At any level of growth, namely seedlings, saplings, poles and trees recorded the necessary data from the type, number, height and diameter of the trunk. Then the obtained data incorporated into tallysheet prepared beforehand. The data obtained were used to calculate the wealth and dominance types (important value index). 2. The thickness of humus Data taken from the forest humus thickness across sub plots that exist in sample plots in the study of vegetation analysis. Determination of measurement points taken by purposive sampling yet located in the plots of vegetation analysis research. The data obtained in the subsequent averaged to obtain an average thickness of humus in the forest. Furthermore humus samples were taken from each plot research and brought to the laboratory for examination ability to absorb water. Humus is calculated thump densitynya and calculated its ability to absorb water for every hectare of topsoil suspect's ability to absorb rainwater. 3. Bulk density of humus Of the 10 research plots were determined randomly drawn each 200 g sample humus for the next bulk densitynya taken and analyzed in the laboratory. Soil samples were also ______________________  Budi Utomo, Faculty of Forestry University Sumatera Utara, Ph. +6281263363000, Email: budi2@usu.ac.id  Correspondance Author: Ameilia Zuliyanti Siregar, Faculty of Agriculture University Sumatera Utara, Ph.+6282273017027, Email: Ameilia@usu.ac.id, azsyanti@gmail.com