Distribution and association pattern of Keruing (Dipterocarpus sp.) in Tangkahan, Gunung Leuser National Park

Keruing ( Dipterocarpus sp.) is a commercially important timber and oil-producing species. Keruing’s wood is of high quality, and its oil is widely used for medicinal purposes. Because of the high price and demand for wood and oil, keruing has become a target for exploitation and causing the population to decrease. Understanding of the keruing population in natural habitats is important for conservation efforts, one of which is in the Gunung Leuser National Park (GLNP) area. The purpose of this study was to analyze the distribution patterns and associations of keruing in the Tangkahan area of GLNP. These are accomplished through the use of a vegetation analysis method with purposefully defined paths based on the presence of keruing. The Ochiai index (Oi), Dice index (Di), and Jackard index (Ji) were calculated for data analysis, while the Morisita index was used to determine the shape of the distribution pattern. The research reveals three keruing species, namely Dipterocarpus haseltii, Dipterocarpus constulatus , and Dipterocarpus elongataus Korth. The keruing distribution showed different patterns at different growth stages. At the seedling and tree stage, the distribution pattern was clustered, while at the sapling and pole stage were uniform. The three keruing species has weak associations with various surrounding species. The species that has the highest association value is Syzygium fastigiatum , which is 0.22.