Tree Species Diversity, Richness and Similarity in Disturbed and Undisturbed Forest of Ketambe Research Station, Southeast Aceh regency

Abstract

Tree species richness in disturbed and undisturbed site of Ketambe Research Station Ketambe, Southeast Aceh regency, Indonesia has been studied from March to May 2018. Research sites were determined using purpossive sampling method. Tree samples were recorded within a plot measuring 400 m2 for each sites with a total of 40 plots. Ecological parameters measured in this study were: Density (D), Relative density (RD), Frequency (F), Relative frequency (RF), Dominance (Do), Relative dominance (RDo), Importance Value Index (IVI), Shannon's diversity index (H'), Margalefs index (R1), and Evenness (E). Estimation of biomass (B) carbon stock (CS) was conducted using allometric equation. Physico-chemical characteristics measured were: air temperature (°C), soil acidity (pH), light intensity (lx), air humidity (%), total organic N (%), and phosphate quantity (ppm) as secondary data. Our study found 79 tree species belonging to 30 families, 61 species in undisturbed site and 47 species in disturbed site. An important species with the highest Importance Value Index (IVI) was Dysoxylum sp.3 in undisturbed site and Macaranga tanarius in disturbed site. The biodiversity was more diverse in undisturbed site (H' = 3.70; R1 = 10.93) than disturbed site on the whole study area (H' = 3.47; R1 = 9.10). The values of evenness (E) varied between 0.66-0.68 among sites. Estimation of tree biomass and carbon stock followed the similar trend with a total of B = 971.299 Mg/ha and CS = 485.649 Mg/ha on the whole study area. The present study revealed that some vital tree species exist in forest area of Ketambe Research Station as carbon sinks along with their high biodiversities from both disturbed and undisturbed regions. The information on tree species diversity may provide a baseline information for conservation of the biodiversity in this area.